What is a good butter substitute for baking cookies? I am looking for something that would contain less fat grams per serving than butter. I have difficulty breaking down fats so I need something that would be gentler on the digestive system. I would greatly appreciate any feedback or ideas.
You are asking not just to substitute for butter, but to reduce the total amount of fat in cookies.
Instead, I recommend taking the approach of making cookies that are naturally lower in fat such as:
or using recipes designed specifically to have lower fat content. If you google "reduced fat cookie recipe" you will find a wealth of results.
One site that looks promising, although I cannot vouch for it as I haven't tried the recipes is:
Another source for lower calorie recipes that are often pretty good, although not targeted specifically at reducing fat is:
Since fat contributes a lot of calories, you may have luck with their recipes.
The benefit of using recipes designed for less fat is that they are (from reputable sources) tested and likely to give you a better outcome than simply trying to substitute in a traditional recipe.
Also, you can try simply reducing the amount of fat in the cookie. This is going to be tricky as it will modify the chemistry, but you may be able to get away with a 1/4 to 1/3 reduction before you get completely unpalatable results, but this will require testing on a recipe by recipe basis. It also will not work well for cookies based on the creaming method, as the fat medium is part of the leavening (the purpose of the creaming method is to create a solid fat/air foam).
One final thought: some people say you can substitute apple sauce. You might try this on a recipe by recipe basis, but it will completely change the cookie. I think you will get better results with recipes created from the ground up to use less fat.