I bake for a living and I test recipes until they behave. This Peanut Butter Cup Cake is one of those reliably festive cakes that looks impressive but is straightforward to build. It combines a tender chocolate layer with a creamy, peanut butter-forward frosting and a glossy ganache finish—plus those miniature peanut butter cups for texture and nostalgia.

What I like about this cake is how the components come together without fuss. The layers are mixed and baked in a single session, the peanut butter frosting comes together in the mixer, and the ganache is quick to make while the cake chills. Timing is the trick: let the layers cool and the frostings set so you get clean slices and bright flavors.

This post gives the recipe steps exactly as written so you can reproduce it in your kitchen, followed by practical tips, troubleshooting, and storage advice from my test kitchen. Read through once, gather your equipment, and then bake with confidence.

Ingredient List

2½cups(312.5g)+ 1 tablespoon all-purpose flour — structure for the cake; measure carefully and level off the cup for accuracy.
3cups(600g)granulated sugar — sweetens and helps the cake stay moist.
1cup(86g)+ 1 tablespoon Dutch-process cocoa powder — provides the deep chocolate flavor; sift to remove lumps.
1tablespoonbaking soda — leavening that reacts with the acid in the buttermilk and coffee.
1½teaspoons(1.5teaspoons)baking powder — additional lift for an even crumb.
1½teaspoons(1.5teaspoons)salt — balances sweetness and enhances chocolate notes.
3eggs,at room temperature — help emulsify and add richness; room temperature eggs incorporate more smoothly.
1½cups(360ml)buttermilk,at room temperature — tenderizes and reacts with baking soda for lift.
1½cups(355.5ml)strong black coffee,hot — intensifies chocolate flavor and thins the batter for a moist cake.
¾cup(163.5ml)vegetable oil — keeps the cake tender and moist; oil makes it stay tender at room temperature.
4½teaspoons(4.5teaspoons)vanilla extract — adds aroma and rounds flavor.
2cups(240g)powdered sugar — base for the peanut butter frosting; sift if lumpy.
2cups(516g)creamy peanut butter — main flavor in the frosting; creamy yields a smooth texture.
10tablespoonsunsalted butter,at room temperature — adds lift and silky mouthfeel to the frosting; room temperature is key for mixing.
1½teaspoons(1.5teaspoons)vanilla extract — second addition in the frosting for depth.
½teaspoon(0.5teaspoon)kosher salt — balances the sweetness in the frosting.
⅔cup(158.67ml)heavy cream — loosens and lightens the frosting when whipped in.
8ounces(226.8g)semisweet chocolate,finely chopped — for the ganache; fine chop helps it melt evenly.
¾cup(178.5ml)heavy cream — heats to melt the chocolate and create ganache.
30miniature peanut butter cups,coarsely chopped, divided — texture and pockets of candy throughout; divided into three equal portions for assembly.

Mastering Peanut Butter Cup Cake: How-To

Preheat the oven to 350°F (175°C). Grease three 8-inch round cake pans, cut and fit parchment rounds into the bottoms, grease the parchment, then flour the insides of the pans and tap out excess; set pans aside.
In the bowl of an electric mixer (or in a large mixing bowl if using a hand mixer), sift together 2½ cups (312.5 g) plus 1 tablespoon all-purpose flour, 3 cups (600 g) granulated sugar, 1 cup (86 g) plus 1 tablespoon Dutch-process cocoa powder, 1 tablespoon baking soda, 1½ teaspoons baking powder, and 1½ teaspoons salt.
In a medium bowl whisk together 3 eggs (room temperature), 1½ cups (360 ml) buttermilk (room temperature), 1½ cups (355.5 ml) strong hot black coffee, ¾ cup (163.5 ml) vegetable oil, and 4½ teaspoons vanilla extract.
Add the wet ingredients to the dry ingredients and mix on medium speed for 2 minutes. Scrape the sides and bottom of the bowl, then mix an additional 20 seconds. The batter will be very thin.
Divide the batter evenly among the three prepared pans. Bake for 20 minutes, then rotate the pans and continue baking until a toothpick inserted into the center comes out almost clean (with a few moist crumbs), about 12 more minutes.
Remove the pans from the oven and cool the cakes in the pans on wire racks for 20 minutes. Carefully turn the cakes out onto wire racks and cool completely.
While the cakes cool, make the peanut butter frosting: in the bowl of an electric mixer fitted with the paddle attachment, combine 2 cups (240 g) powdered sugar, 2 cups (516 g) creamy peanut butter, 10 tablespoons unsalted butter (room temperature), 1½ teaspoons vanilla extract, and ½ teaspoon kosher salt. Mix on medium-low speed until creamy, stopping to scrape down the bowl as needed.
Add 2/3 cup (158.67 ml) heavy cream to the frosting and beat on high speed until the frosting is light and smooth. Do not overbeat.
Coarsely chop the 30 miniature peanut butter cups and divide them into three equal portions of 10 each.
If any cake layers are domed, level them with a serrated knife. Place one cake layer on a serving plate. Spread 1 cup of the peanut butter frosting evenly over the layer, then sprinkle one portion (10) of the chopped peanut butter cups over the frosting.
Place a second cake layer on top, spread another 1 cup of peanut butter frosting evenly, and sprinkle the second portion (10) of chopped peanut butter cups over that frosting.
Place the final cake layer on top (face-down, if you prefer the flattest top). Use the remaining peanut butter frosting to frost the top and sides of the cake, smoothing as desired. Refrigerate the frosted cake for at least 1 hour, until the frosting is set.
While the cake chills, make the chocolate ganache: place 8 ounces (226.8 g) finely chopped semisweet chocolate in a 4-cup measuring cup or heatproof bowl. Heat ¾ cup (178.5 ml) heavy cream in a small saucepan over medium heat until it just comes to a boil. Pour the hot cream over the chopped chocolate and let sit undisturbed for 2 minutes.
Whisk the chocolate and cream starting in the center and gradually working outward until the ganache is completely smooth. Set the ganache aside and whisk occasionally until it has thickened slightly but is still pourable.
If needed, transfer the ganache to a 2-cup measuring cup for easier pouring. Slowly pour the ganache into the center of the chilled cake, allowing it to spread outward and drip over the sides.
Immediately top the ganache-covered cake with the remaining portion (10) of chopped miniature peanut butter cups. Refrigerate the cake for at least 30 minutes to let the ganache set.
Keep the cake refrigerated; remove it about 20 minutes before serving.

The Upside of Peanut Butter Cup Cake

This cake hits three satisfying notes: a deeply chocolatey base, a rich peanut butter buttercream, and a shiny chocolate finish. Texture plays a big role—the cake layers are tender and moist because of the oil and hot coffee, the frosting is silky, and the chopped miniature peanut butter cups add little crunchy-chewy pockets throughout.

It serves well for birthdays, potlucks, or whenever you want something celebratory without complex technique. The assembly is forgiving: the cake dough is thin and easy to pour, the frosting spreads cleanly, and the ganache hides small imperfections while making the cake look professional.

Allergy-Friendly Substitutes

Peanut butter — substitute with a seed butter (sunflower seed butter) for a peanut-free option; use a creamy style for smooth frosting texture.
Cream and butter (dairy) — use full-fat coconut cream and a vegan buttery spread to make the frosting and ganache dairy-free; note texture and flavor will change slightly.
Semisweet chocolate — use dairy-free, vegan chocolate chips if avoiding milk; ensure they’re finely chopped for even melting.
Eggs — for egg-free needs, try a commercial egg replacer or a tested egg-free chocolate layer recipe; this recipe uses eggs for structure so swap only if you have a trusted alternative.

Must-Have Equipment

Three 8-inch round cake pans — for even stacking and baking.
Parchment rounds and cooking spray — to ensure clean removal of layers.
Electric mixer (stand or hand) — makes the frosting and batter consistent and smooth.
Wire racks — for cooling cakes out of their pans.
Serrated knife or cake leveler — for trimming domes and achieving even layers.
4-cup heatproof bowl or measuring cup and a 2-cup container — for making and pouring ganache.
Offset spatula and bench scraper — for frosting and smoothing the cake.
Measuring cups and a scale (optional but recommended) — precise measuring gives consistent results.

Common Errors (and Fixes)

Dry cake — often caused by overbaking. Test early at the minimum bake time and look for a toothpick with a few moist crumbs, not bone-dry crumbs.
Soggy layers after ganache — if you pour warm ganache on a warm cake it can melt the frosting. Chill the frosted cake until the buttercream is firm, then pour cooled-but-still-pourable ganache.
Runny frosting — too-warm butter or overbeating after adding heavy cream can thin the frosting. Chill briefly and then re-whip gently to reach spreadable consistency.
Uneven layers — trim domes with a serrated knife or place the flattest side up when stacking for a stable cake.

Customize for Your Needs

Want more crunch? Stir ½ to 1 cup of coarsely chopped roasted peanuts into part of the frosting before spreading a layer. Prefer more chocolate? Use a darker chocolate for the ganache or fold a tablespoon of cocoa into the frosting for deeper chocolate-peanut contrast.

For smaller crowds, halve the recipe and bake as two 8-inch layers or bake in a 9×13 pan and adjust chilling times. If you like extra caramel notes, drizzle a thin ribbon of caramel between layers before adding the chopped peanut butter cups.

Pro Perspective

Two professional steps make this cake feel like bakery quality: chill the frosted cake before adding ganache, and use room-temperature ingredients for even emulsification. Chilling firms the buttercream so the ganache spreads and drips predictably instead of sliding off.

When making ganache, let the chocolate and cream sit undisturbed for the initial 2 minutes after pouring. That pause allows the heat to soften the chocolate so you stir to a glossy, lump-free ganache with minimal effort. If it looks too thin to drip but is still warm, let it cool while you keep an eye on it—once it thickens slightly it will form prettier drips.

Storage Pro Tips

Store the finished cake refrigerated. The peanut butter frosting holds up well in the fridge; take the cake out about 20 minutes before serving so it returns to a tender, sliceable temperature. For longer storage, freeze individual slices wrapped tightly in plastic wrap and foil; thaw in the refrigerator overnight then bring to near-room temperature before serving.

If you expect to serve the cake at room temperature for several hours, keep it in a cool spot—the frosting will soften in warm conditions. If you’re taking the cake to an event, transport it in a cake box on a flat surface and place it into refrigeration as soon as possible after serving.

Ask the Chef

Q: Can I make the cake layers ahead of time? A: Yes. Wrap cooled layers tightly in plastic and keep in the fridge for up to 48 hours, or freeze up to 2 months. Thaw in the refrigerator before assembling.
Q: Can I use crunchy peanut butter? A: You can, but it will change the frosting texture. If you prefer crunch, use creamy peanut butter for the bulk of the frosting and fold chopped nuts into one layer of filling.
Q: My ganache is grainy. What went wrong? A: Graininess usually results from overheating the chocolate or using chocolate with too little cocoa butter. Gently reheat over a double boiler and whisk until smooth, or add a tablespoon of warm cream and whisk to emulsify.
Q: Can I skip the coffee? A: The coffee intensifies the chocolate, but you can substitute hot water in a pinch. Expect slightly less pronounced chocolate notes.

Before You Go

This Peanut Butter Cup Cake is workaday baking with a celebratory finish. Follow the steps in order, respect chilling times, and rely on the practical tips above for a great result. If you try it, jot down any small tweaks you make—the best versions of a recipe are the ones you adapt to your kitchen and your taste. Happy baking, and don’t forget to save a slice for yourself.

Peanut Butter Cup Cake

Decadent layered chocolate cake filled and frosted with creamy peanut butter frosting, topped with chocolate ganache and chopped miniature peanut butter cups.

Print Recipe Pin Recipe

Prep Time 3

Cook Time 32

Total Time 3 32

Servings: 12 servings

Course: Dessert

Ingredients Equipment Method Notes

Ingredients

2 1/2 cups 312.5 g+ 1 tablespoon all-purpose flour
3 cups 600 ggranulated sugar
1 cup 86 g+ 1 tablespoon Dutch-process cocoa powder
1 tablespoonbaking soda
1 1/2 teaspoons 1.5 teaspoonsbaking powder
1 1/2 teaspoons 1.5 teaspoonssalt
3 eggs at room temperature
1 1/2 cups 360 mlbuttermilk, at room temperature
1 1/2 cups 355.5 mlstrong black coffee, hot
3/4 cup 163.5 mlvegetable oil
4 1/2 teaspoons 4.5 teaspoonsvanilla extract
2 cups 240 gpowdered sugar
2 cups 516 gcreamy peanut butter
10 tablespoonsunsalted butter at room temperature
1 1/2 teaspoons 1.5 teaspoonsvanilla extract
1/2 teaspoon 0.5 teaspoonkosher salt
2/3 cup 158.67 mlheavy cream
8 ounces 226.8 gsemisweet chocolate, finely chopped
3/4 cup 178.5 mlheavy cream
30 miniature peanut butter cups coarsely chopped, divided

Equipment

8-inch round cake pans
Parchment Paper
Electric Mixer
paddle attachment
wire racks
Measuring Cups
Measuring Spoons
4-cup measuring cup or heatproof bowl
Small Saucepan
serrated knife
2-cup measuring cup (optional)

Method

Instructions

Preheat the oven to 350°F (175°C). Grease three 8-inch round cake pans, cut and fit parchment rounds into the bottoms, grease the parchment, then flour the insides of the pans and tap out excess; set pans aside.
In the bowl of an electric mixer (or in a large mixing bowl if using a hand mixer), sift together 2½ cups (312.5 g) plus 1 tablespoon all-purpose flour, 3 cups (600 g) granulated sugar, 1 cup (86 g) plus 1 tablespoon Dutch-process cocoa powder, 1 tablespoon baking soda, 1½ teaspoons baking powder, and 1½ teaspoons salt.
In a medium bowl whisk together 3 eggs (room temperature), 1½ cups (360 ml) buttermilk (room temperature), 1½ cups (355.5 ml) strong hot black coffee, ¾ cup (163.5 ml) vegetable oil, and 4½ teaspoons vanilla extract.
Add the wet ingredients to the dry ingredients and mix on medium speed for 2 minutes. Scrape the sides and bottom of the bowl, then mix an additional 20 seconds. The batter will be very thin.
Divide the batter evenly among the three prepared pans. Bake for 20 minutes, then rotate the pans and continue baking until a toothpick inserted into the center comes out almost clean (with a few moist crumbs), about 12 more minutes.
Remove the pans from the oven and cool the cakes in the pans on wire racks for 20 minutes. Carefully turn the cakes out onto wire racks and cool completely.
While the cakes cool, make the peanut butter frosting: in the bowl of an electric mixer fitted with the paddle attachment, combine 2 cups (240 g) powdered sugar, 2 cups (516 g) creamy peanut butter, 10 tablespoons unsalted butter (room temperature), 1½ teaspoons vanilla extract, and ½ teaspoon kosher salt. Mix on medium-low speed until creamy, stopping to scrape down the bowl as needed.
Add 2/3 cup (158.67 ml) heavy cream to the frosting and beat on high speed until the frosting is light and smooth. Do not overbeat.
Coarsely chop the 30 miniature peanut butter cups and divide them into three equal portions of 10 each.
If any cake layers are domed, level them with a serrated knife. Place one cake layer on a serving plate. Spread 1 cup of the peanut butter frosting evenly over the layer, then sprinkle one portion (10) of the chopped peanut butter cups over the frosting.
Place a second cake layer on top, spread another 1 cup of peanut butter frosting evenly, and sprinkle the second portion (10) of chopped peanut butter cups over that frosting.
Place the final cake layer on top (face-down, if you prefer the flattest top). Use the remaining peanut butter frosting to frost the top and sides of the cake, smoothing as desired. Refrigerate the frosted cake for at least 1 hour, until the frosting is set.
While the cake chills, make the chocolate ganache: place 8 ounces (226.8 g) finely chopped semisweet chocolate in a 4-cup measuring cup or heatproof bowl. Heat ¾ cup (178.5 ml) heavy cream in a small saucepan over medium heat until it just comes to a boil. Pour the hot cream over the chopped chocolate and let sit undisturbed for 2 minutes.
Whisk the chocolate and cream starting in the center and gradually working outward until the ganache is completely smooth. Set the ganache aside and whisk occasionally until it has thickened slightly but is still pourable.
If needed, transfer the ganache to a 2-cup measuring cup for easier pouring. Slowly pour the ganache into the center of the chilled cake, allowing it to spread outward and drip over the sides.
Immediately top the ganache-covered cake with the remaining portion (10) of chopped miniature peanut butter cups. Refrigerate the cake for at least 30 minutes to let the ganache set.
Keep the cake refrigerated; remove it about 20 minutes before serving.