If you're a top pastry chef making fine French pastries, you probably don't want to substitute peanut butter for butter, but the home cook can use peanut butter in a pinch as the main fat in many recipes. Vegans in particular may be happy to know that, if it's done correctly, using peanut butter as a butter substitute in baked goods doesn't result in a product that looks and feels like a lead hockey puck. The key is to consider the taste, texture and properties of peanut butter when using it as a replacement for butter in any recipe.
Butter Versus Peanut Butter
To know how to substitute peanut butter for butter, it's important to know butter's function in a recipe. Creaming butter with sugar creates air pockets that act as leavening, so your baked goods are tender and flaky with a light, moist crumb. Baked items made with butter typically have a good mouth-feel, plus the butter imparts a unique flavor that can't be duplicated. Using peanut butter alters the flavor, infusing end products with a nutty taste, plus it can make your baked goods somewhat dense and heavy.
Substituting Peanut Butter for Butter
Unlike other fats and oils, butter, depending on the style and salt content, is at least 80 percent fat, with milk solids and water making up the remaining 20 percent; on the other hand, peanut butter is only 50 percent fat. It contains 25 percent protein, fiber and other carbohydrates in addition to fat. To effectively substitute peanut butter for butter in a recipe, first combine equal parts creamy peanut butter and oil; use the mixture cup for cup as you would use butter in cakes, muffins, cookies, brownies or quick breads.