Baking is a craft of precision, but let's be real: If you go to the trouble of making a cake or cookies, anyone who is lucky enough to get them is not going to complain, even if you had to make a few swaps here and there. A quick note on substitutions, though: Using what you have is about managing your expectations. Here are 9 baking substitutions that can aid you!
If you need to swap out eggs, it's helpful to know what you're using the eggs for in the recipe. In cases where you don't need to whip eggs or separate yolks and whites, one easy trick is to substitute 1/4 cup of carbonated, unflavored water for every large egg you need. You can also combine 2 tablespoons of water, 2 teaspoons baking powder, and 1 teaspoon vegetable oil for every large egg.
A 1/4 cup applesauce or mashed banana per egg needed can also work. If you have ground flaxseeds or chia seeds on hand, add 1 tablespoon of seeds to 3 tablespoons of water and stir to make a paste, which will also be the equivalent of an egg. If you need egg whites, use aquafaba, the cooking liquid in a can of chickpeas.
For every cup of cake flour called for, measure a cup of all-purpose flour, remove 2 tablespoons of flour from each cup, then add in 2 tablespoons of cornstarch or arrowroot powder. The cornstarch will help inhibit the production of gluten, allowing for the delicate cake crumb that cake flour gives your baking project.
On most occasions, if you have bread flour and not all-purpose (or vice versa), you can just make an easy one-to-one swap.
Since baking powder is actually made from baking soda, you can use baking powder as a substitute for baking soda. You do need to adjust the proportions, though — use three times the amount of baking powder as a substitute for baking soda.
For every teaspoon of baking powder you need, combine 1/2 teaspoon of cream of tartar with 1/4 teaspoon of baking soda. If you don't have cream of tartar, you can use another acid you have on hand, like lemon juice or vinegar.
The easiest substitute for brown sugar is granulated sugar. If you happen to have molasses, you can make an even closer substitute by adding the dark syrup to regular sugar.
If you don't have chocolate chips but you do have bars of chocolate, just chop those up and use them as a one-to-one replacement. If you have neither, but you do have unsweetened chocolate, you can do the same ratio of chocolate and sugar per ounce as you would to replace semi sweet chocolate.
If you don't have buttermilk and you need it for baking, swap in a cup of milk soured with a tablespoon of lemon or white vinegar for every cup of buttermilk you need.
If you need sour cream and you don't have any, you can swap in an equal amount of yogurt, mayonnaise, or pureed cottage cheese.