Then after it cools, it should be good to mix into your recipe! We do not recommend this substitute in baking recipes with high oil content, as it is prone to change the consistency of your batter. How to Substitute for Oil. Some substitutions in recipes can get really finicky, but for the most part, these oil substitutions are pretty simple. In that case, you can substitute something else, like mayonnaise, for the oil in a boxed cake mix. Reasons to Sub Mayo for Oil. If you’re baking a cake and suddenly discover you’re out of vegetable oil, you might want to substitute something for the oil so you don’t have to run out to the store.