Peanut butter for shortening in brownies

Question

My mother's old (1940s?) cookbook had a recipe for brownies which included a substitution of peanut butter for the shortening.They were not swirl brownies. Unfortunately the cookbook is gone and now I'm reading that you can't use peanut butter in place of shortening. Which is right?

Answer 1

It's probably going to be a bit odd if you try it as a direct substitution, (peanut butter is not all fat) but generally with some adjustments it's likely to work. Having lost the original recipe, assuming you can't find it again experimentation and tasting would be the logical approach.

As for "which is right" if you have actually eaten the brownies made with peanut butter instead of shortening, obviously the original recipe does, in fact, work, however it was written. Beware of books (or more often web publications) claiming things that are not actually true, or that are only "true" in some narrow sense.

One comment mentions adjusting for sugar - that, of course, would depend on the peanut butter you use - some have added sugar and/or salt, and some do not. If the one you use does, then you should account for the sugar and/or salt added by using the peanut butter and reduce them in the other ingredients. If you are starting with a recipe using shortening, you likely need a bit more peanut butter (so the amount of fat contributed by the peanut butter is equivalent to the amount of shortening) and a bit less flour since the non-fat peanut solids will basically act as "peanut flour" in the recipe.