Browse the internet for viable ingredient substitutions and you'll see suggestions of replacing cream with evaporated milk, or white flour with black bean purée, or two eggs with one banana, or butter with avocado, or canola oil with Greek yogurt... the list goes on (and images of cake disappointments flash through my mind).
While cooking likely leaves room for experimenting (and for covering up mistakes), baking is riskier: Substitute black bean purée for all-purpose flour (or a mashed avocado for a stick of butter) in your cookie dough, and I can almost guarantee you're not going to come away with a product you'll want to serve to friends.
So before you substitute willy-nilly, ask yourself: Will the swap alter the fundamental structure and composition of the final product? More specifically...
- Will I be changing the ratio of wet ingredients to dry ingredients (by swapping in oil for butter, for example, or honey for granulated sugar)?
- Will I be altering the amount of fat or sugar in the recipe (by subbing applesauce for oil or sugar or skim milk for cream)?
- Will I be futzing with the chemistry in some way? (Joanne Chang, author of Baking with Less Sugar, explains, you may need to adjust the oven temperture to account for a sugar-sub that caramelizes at a lower temperature, for example.)
- Will I be removing gluten (by subbing almond flour for all-purpose), leaveners (when, in some instances, replacing an an egg with a vegan alternative), or another ingredient that might threaten the structural integrity?
- Will I be making a transformative step of the recipe impossible (whipping egg whites, creaming butter and sugar, kneading dough)?
In simpler terms: Is the ingredient that's being added similar in fat/sugar/consistency/structure/acidity to what it's replacing? Tahini and peanut butter, for example, are viable for swapping: They both have 4 grams of fat per tablespoon and a similar viscosity (of course, you'll have to keep the flavor differences in mind, too). Tahini and avocado are not.
Alice Medrich warns, as general rules, against subbing liquid fats for butter; liquid sweeteners for sugar; acidic ingredients (buttermilk, lemon juice, vinegar) for milk or water; or gluten-free flour for over 50% of wheat flour without careful consideration.
With so many rules and warnings, what can be freely exchanged?
Buttermilk, yogurt (plain and Greek), sour cream, labneh, and crème fraîche: As long as you consider the thickness of the product and the flexibility of your recipe, you can get away with playing musical chairs with the gamut of tangy dairy products. Read Alice Medrich's guide for subbing dairy products into baking recipes here.
Milk and soy milk, which are similar in terms of protein, fat, and fiber. (See a full rundown of non-dairy milk swaps here.)
Olive oil and vegetable oil, especially in cakes, granola, quick breads, and muffins, with the caveat—and sometimes advantage—that olive oil has a much stronger flavor.
Pumpkin or winter squash purée, applesauce, pear sauce, and mashed bananas, keeping in mind that the sweetness and moisture levels might vary slightly.
Granulated sugar, brown sugar (light or dark), turbinado or raw sugar, and muscovado, knowing that some are moister than others (and you may have to add a bit more liquid or a bit more flour to counteract that).
Whole-wheat flour and all-purpose, though the former will give you a heartier, sturdier end result than the latter and might not be ideal for very delicate baked goods.
Various nut meals/flours (I've substituted hazelnut meal for almond meal, for example), bearing in mind that the amount of fat varies a bit depending on the type of nut. Same goes for various nut and seed butters, although the consistency and thickness may vary depending on type of nut and how it was processed.
Buttermilk for regular milk mixed with a spoonful of vinegar or lemon juice. Read more on how to improvise buttermilk here. But if you're baking something that depends heavily on tangy buttermilk flavor (biscuits, for example) rather than simply the difference in acidity, it might be worth seeking out high-quality bottled buttermilk from the store or market.
Cake flour for 14 tablespoons all-purpose flour whisked with 2 tablespoons cornstarch.
Self-rising flour for 1 cup all-purpose flour plus 1 1/2 teaspoons baking powder and 1/4 teaspoon salt.
Have you had success with crazy ingredient swaps that actually worked? Tell us in the comments below!