If you’ve ever tasted the tangy, dreamy green dressing at the Old Spaghetti Factory and wanted to bottle that magic at home, you’re in the right place. This Old Spaghetti Factory Creamy Pesto Dressing: Easy Copycat Recipe gives you a silky, herb-forward dressing that brightens salads, sandwiches, and veggie bowls. It’s ready in minutes, keeps well in the fridge, and uses simple pantry staples—perfect for busy weeknights or weekend meal prep.

Why you’ll love this dressing

This dressing balances creaminess and herbaceousness in a way that feels indulgent but still approachable. The mayonnaise and buttermilk create a smooth, tangy base while vegetable oil gives body and shine. Grated Romano cheese adds umami and depth, crushed dried basil brings classic pesto notes, and a little minced garlic plus hot pepper sauce round the flavor profile with a bit of bite. It’s also endlessly versatile: use it as a salad dressing, a dip for crudités, or a spread for wraps.

Equipment

Medium mixing bowl or a jar with a tight lid
Whisk or fork (or an immersion blender for an extra-smooth finish)
Measuring cups and spoons
Rubber spatula or spoon
Airtight container or jar for storing

Ingredients

3/4 cup vegetable oil
1 cup mayonnaise
3/4 cup buttermilk
2 tablespoons grated Romano cheese
2 tablespoons crushed dried basil
1/2 teaspoon salt
1 teaspoon minced garlic
Hot pepper sauce, to taste

Taste and texture notes

The texture should be creamy but pourable—thicker than a vinaigrette yet not as heavy as a dip. If you prefer a looser dressing, add another tablespoon or two of buttermilk until you reach your desired consistency. For a thicker spread, reduce the buttermilk slightly. The dried basil will rehydrate in the wet ingredients and infuse the dressing with that familiar pesto-like aroma. Adjust the hot pepper sauce slowly; a few drops add a background warmth, while a half-teaspoon or more will give a noticeable kick.

Step-by-step instructions

Below are clear, rewritten steps based on the original recipe order, preserving all ingredient amounts. Follow them exactly for the best copycat result.

Measure and gather all ingredients. Place 3/4 cup vegetable oil, 1 cup mayonnaise, and 3/4 cup buttermilk on your work surface so everything is ready to combine.
In a medium mixing bowl (or a jar if you prefer to shake the dressing), add 1 cup mayonnaise first. This gives the emulsion a stable base.
Pour in 3/4 cup buttermilk to the bowl with the mayonnaise. Stir gently to begin combining the two creamy ingredients into a smooth mixture.
Slowly drizzle in 3/4 cup vegetable oil while whisking continuously. Adding the oil gradually helps the dressing emulsify and reach a silky texture. If you’re using an immersion blender, add the oil in a steady stream while blending on low.
Add 2 tablespoons grated Romano cheese to the mixture. Whisk until the cheese is evenly distributed and starts to melt slightly into the dressing.
Sprinkle in 2 tablespoons crushed dried basil. Fold or whisk the basil into the dressing until it is evenly dispersed and rehydrated by the liquids.
Season the dressing with 1/2 teaspoon salt, then add 1 teaspoon minced garlic. Stir well so the garlic and salt blend throughout the dressing.
Finish by adding hot pepper sauce to taste. Start with a few drops, mix, then taste. Increase slowly until the heat level suits you.
Taste and adjust: if the dressing tastes too thick, whisk in another tablespoon or two of buttermilk. If it needs more herb flavor, add a pinch more crushed dried basil. If it needs more tang, a small splash of lemon juice or a teaspoon of white vinegar can help, added sparingly.
Transfer the dressing to an airtight container or glass jar. Seal and chill for at least 30 minutes to let the flavors meld. The dressing will thicken slightly as it chills.

Storage and shelf life

Store your dressing in a sealed container in the refrigerator. It will stay fresh for about one week. If separation occurs, simply give it a quick shake or whisk before using. Keep an eye on the garlic flavor over time—fresh minced garlic can mellow the longer it sits, so taste before serving.

Serving suggestions

Here are some favorite ways to use this dressing that highlight its creamy, herby character:

Drizzle over a mixed greens salad with cherry tomatoes, cucumber, and shaved carrots for a quick weeknight meal.
Use as a creamy sauce for a pasta salad with rotini, roasted red peppers, and black olives.
Spread on a toasted sandwich or wrap in place of mayonnaise for extra flavor.
Serve as a dip with crisp vegetables, pita chips, or as a sauce for grilled chicken or shrimp.
Toss with roasted potatoes or drizzle over grilled vegetables to add an herb-forward finish.

Tips and swaps

If you prefer a fresher basil flavor, swap one tablespoon of the crushed dried basil for one tablespoon of finely chopped fresh basil, keeping the rest dried as listed. Add fresh basil at the end to preserve its bright color.
For a lighter version, use a light mayonnaise and low-fat buttermilk—note this will change the richness slightly but maintains the overall flavor.
If you don’t have Romano cheese, you can substitute an equal amount of another hard, aged cheese with similar saltiness and umami, keeping the same measurement.
To achieve an ultra-smooth texture, blend the dressing briefly with an immersion blender or standard blender until homogeneous.

Common questions

Can I make this dressing ahead of time? Yes. It actually benefits from a short rest in the refrigerator—30 minutes to a few hours—to let the dried basil rehydrate and the flavors marry. Keep it sealed and chilled until ready to use.

How spicy will it be? The heat level depends entirely on how much hot pepper sauce you add. Start conservatively and add more after tasting. A few drops give a gentle background warmth, while a teaspoon or more will be assertive.

What if my dressing separates? Separation is normal because oil and buttermilk can separate over time. Shake or whisk it back together before serving; it will emulsify quickly with a quick stir.

Why this version works

This version captures the essence of a classic creamy pesto-style dressing by combining the stability of mayonnaise with the tang of buttermilk and the richness of oil. Romano cheese contributes a salty, savory backbone while dried basil recreates the pesto aroma without needing fresh leaves and a food processor. The minced garlic and hot pepper sauce lift the whole thing with bright, savory, and piquant notes—together they recreate the familiar profile you love from the restaurant, but with home-kitchen simplicity.

Nutrition snapshot (approximate)

Per 2-tablespoon serving: expect a calorie-dense dressing due to oil and mayonnaise. It will be high in fat and moderate in sodium because of the cheese and salt. For exact numbers, use a nutrition calculator and plug in the specific brands you use.

Final thoughts

This Old Spaghetti Factory Creamy Pesto Dressing: Easy Copycat Recipe is a reliable, flavorful staple to keep in your fridge. It’s easy enough for everyday meals but rich enough to make a simple salad feel special. The ingredients are pantry-friendly, and the step-by-step method is intentionally straightforward so you can recreate that classic restaurant flavor anytime.

Make a batch this weekend and try it on a big bowl of crisp greens, or use it to elevate grilled veggies and sandwiches throughout the week. Once you taste it, you’ll find it earns a permanent spot among your go-to dressings.

Old Spaghetti Factory Creamy Pesto Dressing: Easy Copycat Recipe

A rich, tangy creamy pesto-style dressing that replicates the Old Spaghetti Factory favorite with simple pantry ingredients.

Print Recipe Pin Recipe

Prep Time 10

Cook Time 5

Total Time 15

Servings: 10 servings

Ingredients Equipment Method Notes

Ingredients

3/4 cup vegetable oil
1 cup mayonnaise
3/4 cup buttermilk
2 tablespoons grated Romano cheese
2 tablespoons crushed dried basil
1/2 teaspoon salt
1 teaspoon minced garlic
hot pepper sauce to taste

Equipment

Mixing Bowl
Whisk
Measuring cups and spoons
Spoon
container with lid

Method

In a mixing bowl, whisk together 1 cup mayonnaise and 3/4 cup vegetable oil until smooth and slightly emulsified.
Add 3/4 cup buttermilk, 2 tablespoons grated Romano cheese, 2 tablespoons crushed dried basil, 1 teaspoon minced garlic, and 1/2 teaspoon salt to the bowl; whisk until fully combined.
Season with hot pepper sauce to taste and whisk to incorporate.
Transfer the dressing to a covered container and refrigerate overnight to allow the flavors to meld before serving.