All the cakes I've made in the past, i've used the store bought cake mix. And i've discovered that sometimes the cake is almost too soft, and when a decorate and put fondant of the cake, the cake seems to not be able to hold it too well. So I was wondering if anyone had any ideas to what i can add to the cake mix. I've heard of "doctoring" a recipe, like adding sour cream, but i'm not sre how much to add. Any ideas?