How To Substitute Cornstarch For Butter In Pasta Sauce
When it comes to making pasta sauce, there's one thing that really ties everything together: butter. Butter can typically make any dish taste better, but when added to pasta sauce specifically, it does more than just improve the flavor, Taste of Home explains. Thanks to its high fat content, butter also acts as an emulsifier, giving the sauce a distinct richness and much more velvety consistency.
When you don't have any butter on hand, you might assume that your pasta sauce will turn out subpar as a result, but cookbook author J. Kenji López-Alt revealed in a Serious Eats article that it doesn't have to be the case — as long as you have cornstarch and olive oil. Olive oil alone is a good substitute for butter in terms of taste, however, it doesn't have the same emulsifying properties. That's where the cornstarch comes in. "Starch helps emulsify sauces by physically impeding fat molecules from coalescing in a fat and water mix," López-Alt explained. That means when you combine cornstarch and olive oil in a pasta sauce, it effectively mimics the effect of butter.
How much cornstarch do you need in place of butter?
When adding cornstarch to any sort of sauce, whether it be for pasta or another dish, typically you'll make a slurry combining cornstarch with a liquid. While this method is effective for thickening, the goal when adding cornstarch to pasta sauce is to create a buttery consistency. In this case therefore, you won't need to be so heavy handed with the cornstarch, nor will you have to make a slurry at all.
According to J. Kenji López-Alt's Serious Eats article, a half teaspoon of cornstarch is enough for two servings of pasta. To add it into your sauce, first substitute the butter for high quality olive oil. Add it in at the same point you would normally add the butter, then mix in the appropriate ratio of cornstarch. When your sauce cooks down, you'll find that instead of the olive oil collecting at the bottom of the bowl, it will emulsify with the rest of the sauce and stick to the pasta just like if you used butter.