I have a family recipe for cookies, that I would like to turn into a cake, since the cookies come out soft (not crunchy), but honestly don't even know where to start.
Can you share the recipe? What is it about the cookies that you like so much that you want them to be cake? Cakes generally have more liquid, eggs, and leavening than cookies. You beat the liquid ingredients longer to incorporate air so that the cake rises. If there's a specific flavor profile you're trying to create, we could probably help direct you to a recipe that could be modified. But if you really want to understand the science, and make it yourself, check out Michael Ruhlman's Ratio and/ or Shirley Corriher's Bakewise.
There are lots of other books on the science of baking, but those are the first two that came to mind. Good luck!
I wouldn't use a cookie recipe for a cake, unless you're looking to make a cookie cake. For instance, a large chocolate chip cookie pressed into a pie plate
I've made cookies into cake-like bars by beating a couple of eggs into the sugar & butter before I add the rest of the ingredients. Hope that helps.
Couldn't edit my question, so have to add a bit here. The primary ingredients, the biggest bulk, is 2 cups brown sugar, and 4 cups flour. Given it makes great cookies, having swapped out every baking spice I could so far, figured I'd try it as a cookie-cake kind of thing.