Crustless Mushroom Quiche
I make this crustless mushroom quiche when I want something honest, filling, and fast to the table. It’s one of those reliable recipes that survives busy mornings, lazy dinners, and the occasional need to feed a crowd without much fuss. The mushrooms add earthiness, the Swiss brings a gentle nuttiness, and the eggs-and-cream custard keeps everything silky without a crust getting in the way.
There’s no pre-made crust to fuss with, which means fewer steps and a lighter result. If you’re watching carbs or just prefer something less fiddly than a pastry shell, this version is for you. It’s sturdy enough to slice for brunch company and forgiving enough to make ahead and rewarm.
I’ll walk you through the ingredients, the exact steps, and practical tips I’ve learned from making this many times. No fluff—just what works, what to avoid, and a few tweaks to make it your own.
What Goes In
- 1 lb ground beef — provides savory protein and a meaty base; browning concentrates the flavor.
- 8 oz white mushrooms, sliced — brings moisture and umami; add toward the end of browning so they don’t over-shrink.
- 2 green onions, thinly sliced, greens only — mild onion flavor and color; stir in raw for brightness.
- 1 ½ c Swiss cheese, shredded — melts smoothly and adds a nutty, creamy note that complements beef and mushrooms.
- 1 handful of spinach, chopped — a quick green that wilts into the filling for color and freshness.
- 10 eggs — the structure and custard base; whisk thoroughly for an even texture.
- 1 1/2 c heavy cream — gives richness and a tender, silky custard.
- 1 c whole milk — lightens the custard slightly so it’s not overly dense.
- 1/2 tsp sea salt — seasons the whole dish; adjust if your cheese is salty.
- 1/2 cracked pepper — fresh-cracked is best for aroma; balances the cream.
- 1/4 tsp crushed red pepper, optional — a faint heat if you like a whisper of spice.
The Method for Crustless Mushroom Quiche
- Preheat the oven to 350°F. Lightly oil-spray a 9×13-inch baking pan (or a large casserole dish or two 9-inch pie pans).
- Prepare the produce: slice the 8 oz white mushrooms, thinly slice the green onion greens (2 green onions, greens only), and chop the handful of spinach. Have the 1 1/2 cups shredded Swiss cheese ready.
- Brown 1 lb ground beef in a skillet over medium-high heat, breaking it into pieces as it cooks. Add the sliced mushrooms about 3 minutes before the beef is done. Cook until the beef is no longer pink.
- Remove the skillet from the heat, drain off excess grease (or blot with paper towels), and transfer the meat-and-mushroom mixture to a bowl to cool briefly so it won’t cook the eggs.
- In a large mixing bowl, add all 10 eggs and whisk for about 2–3 minutes until well blended. Add 1 1/2 cups heavy cream, 1 cup whole milk, 1/2 tsp sea salt, 1/2 tsp cracked pepper, and 1/4 tsp crushed red pepper (optional). Whisk another 2–3 minutes until the mixture is frothy. (You may use a blender or electric mixer if you prefer.)
- Add the cooled beef-and-mushroom mixture, the shredded Swiss cheese, the sliced green onion greens, and the chopped spinach to the egg mixture. Stir until evenly combined.
- Pour the mixture into the prepared pan(s) and smooth the top.
- Bake in the preheated oven. Begin checking at 28 minutes; total bake time will be about 35–40 minutes. The quiche is done when the edges are golden brown and the center is set but may have a slight wobble.
- Remove from the oven and let the quiche cool for about 10 minutes before slicing and serving.
Why This Recipe Belongs in Your Rotation
This is a no-nonsense, dependable dish that fits many roles: breakfast for a crowd, a weeknight dinner, or a portable potluck contribution. The crustless format cuts prep time and calories without sacrificing comfort or flavor. Once you’ve browned the beef and combined the custard, the oven does most of the work.
It’s also extremely forgiving. If life interrupts you mid-bake, a few extra minutes in a warm oven won’t ruin it. If you want to shift the meal profile—lighter for brunch or heartier for dinner—the components allow that. The texture is custardy and moist, not rubbery, if you follow the whisking and baking timings carefully.
Easy Ingredient Swaps
Keep swaps simple and anchored to what’s already in the dish to avoid guessing at amounts.
- Use a bit more whole milk and a touch less heavy cream to make the custard slightly lighter while keeping the overall balance.
- If you prefer less meat, reduce the ground beef and add more mushrooms and spinach in its place to maintain volume and moisture.
- Omit the crushed red pepper entirely if you don’t want heat; the quiche will still be well seasoned from the pepper and salt.
- For a milder onion note, use only half the green onion greens; for more brightness, add them all.
Prep & Cook Tools
These are the practical tools that make this recipe straightforward and foolproof.
- Large skillet — for browning the ground beef and softening the mushrooms.
- 9×13-inch baking pan or casserole dish — the recipe is designed for this size for even baking.
- Mixing bowl and whisk (or blender/electric mixer) — whisking aerates the eggs for a silkier custard.
- Measuring cups and spoons — to keep the egg-to-dairy ratio accurate.
- Spatula or wooden spoon — for scraping the bowl and folding ingredients together.
- Paper towels — for blotting excess grease if needed after browning the beef.
Avoid These Mistakes
Small errors are common but easy to avoid. Here’s what I see most often.
- Adding the mushrooms too early while browning the beef. They’ll release liquid and steam rather than brown; add them about 3 minutes before the beef is done.
- Pouring the filling into the pan while the meat is still hot. That continues to cook the eggs and can make the custard uneven. Let the meat cool briefly.
- Under-whisking the eggs and dairy. A well-blended, frothy mixture traps air and yields a lighter set.
- Baking at too high a temperature. 350°F gives even cooking; higher temps risk over-browning the edges while the center remains underdone.
- Skipping the resting time after baking. The quiche needs about 10 minutes to finish setting and to make clean slices.
Seasonal Adaptations
Minor adjustments keep this quiche feeling seasonal without changing the core recipe.
- Spring: Add more chopped spinach for a bright, green lift. The recipe already uses spinach, so increase the handful if you like.
- Autumn/Winter: Use mushrooms that are in season—if you have a mix of cremini and white mushrooms on hand, they work well together. Stick to the same weight so the moisture balance stays right.
- Summer: Add fresh herbs from the garden (finely chopped) right before serving for freshness; add sparingly so you don’t overwhelm the custard.
What Could Go Wrong
Here are likely problems and how to fix or prevent them.
- Soggy texture: caused by excess liquid from mushrooms or spinach. Prevent by sautéing mushrooms properly and chopping spinach finely; if the meat mixture seems wet, give it a minute to cool and let any liquid settle, or blot lightly with paper towels.
- Rubbery eggs: usually the result of overbaking or baking at too high a temperature. Check at 28 minutes and remove when the center is just set with a slight wobble.
- Over-salted result: if your Swiss cheese is very salty, reduce the added sea salt by half and taste the filling components before mixing.
- Uneven baking: use a single 9×13 pan unless you know your oven heats unevenly. If using two 9-inch pie pans, rotate them halfway through baking.
Cooling, Storing & Rewarming
Proper cooling and storage will keep the quiche safe and maintain texture.
- Cooling: Let the quiche rest on a rack for about 10 minutes after baking so it finishes setting. Longer cooling is fine; cover loosely after it comes to room temperature.
- Refrigerating: Wrap tightly or store in an airtight container and refrigerate for up to 4 days. Slice before storing for easy reheating portions.
- Freezing: You can freeze slices wrapped individually for up to 2 months. Thaw overnight in the fridge before reheating.
- Reheating: Warm slices in a 325°F oven for 10–15 minutes until heated through, or microwave single slices for 45–90 seconds, depending on power. Oven reheating preserves texture best.
Reader Questions
Q: Can I make this vegetarian? A: Yes. Omit the ground beef and increase the mushrooms and spinach, or add additional vegetables you already have on hand (see swaps). Sauté extra mushrooms well to remove excess moisture.
Q: Can I bake this in individual portions? A: You can split the mixture into two 9-inch pie pans as the original directions suggest, or use smaller ramekins. Adjust bake time and check early—the smaller the dish, the quicker it sets.
Q: Can I use lower-fat dairy? A: The texture will change. Using more whole milk and less heavy cream will make a slightly less rich custard but still edible. Keep proportions similar to maintain the ratio of liquids to eggs.
Q: Why 10 eggs? A: Ten eggs provide structure and a firm custard for the amount of dairy and fillings used. Reducing eggs without adjusting other liquids will make a looser set.
See You at the Table
This crustless mushroom quiche is one of those recipes I return to when I want a predictable, satisfying meal without drama. It’s flexible, forgiving, and straightforward to scale. Follow the method, mind the small tips—especially cooling the meat before combining—and you’ll have even, tender slices that reheat well and travel nicely.
Make it on a weekend to enjoy leftovers all week, or bring it to a brunch and watch how quickly it disappears. If you try it, tell me how you adapt it: more spinach, extra mushrooms, or maybe doubling the cheese. I love hearing what makes a recipe yours.
Crustless Mushroom Quiche
Ingredients
Equipment
Method
- Preheat the oven to 350°F. Lightly oil-spray a 9×13-inch baking pan (or a large casserole dish or two 9-inch pie pans).
- Prepare the produce: slice the 8 oz white mushrooms, thinly slice the green onion greens (2 green onions, greens only), and chop the handful of spinach. Have the 1 1/2 cups shredded Swiss cheese ready.
- Brown 1 lb ground beef in a skillet over medium-high heat, breaking it into pieces as it cooks. Add the sliced mushrooms about 3 minutes before the beef is done. Cook until the beef is no longer pink.
- Remove the skillet from the heat, drain off excess grease (or blot with paper towels), and transfer the meat-and-mushroom mixture to a bowl to cool briefly so it won’t cook the eggs.
- In a large mixing bowl, add all 10 eggs and whisk for about 2–3 minutes until well blended. Add 1 1/2 cups heavy cream, 1 cup whole milk, 1/2 tsp sea salt, 1/2 tsp cracked pepper, and 1/4 tsp crushed red pepper (optional). Whisk another 2–3 minutes until the mixture is frothy. (You may use a blender or electric mixer if you prefer.)
- Add the cooled beef-and-mushroom mixture, the shredded Swiss cheese, the sliced green onion greens, and the chopped spinach to the egg mixture. Stir until evenly combined.
- Pour the mixture into the prepared pan(s) and smooth the top.
- Bake in the preheated oven. Begin checking at 28 minutes; total bake time will be about 35–40 minutes. The quiche is done when the edges are golden brown and the center is set but may have a slight wobble.
- Remove from the oven and let the quiche cool for about 10 minutes before slicing and serving.
Notes
A quiche is done when the egg mixture is set but slightly wobbly in the center.Don’t overcook the quiche or you can lose the smooth creamy texture you want out of a quiche. The edges and around the center will be set but the middle should still have a slight movement to it.
You can cook this in two separate 9 inch pie pans.If you prefer a round, pie shaped quiche, you can use two pie pans. Or you can easily half this recipe and make it in just one pie pan instead.
