Help! I use the Cake Bible's White Butter Cake recipe. Cupcakes will turn out spectacular, larger cakes, not so much. Yesterday I made a 9" heart shaped cake that took forever to bake and the end result was gummy. I do make my own cake flour sub with cornstarch and ap flour and sift 5 times. I also weigh my ingredients as opposed to measure. I have 2 wedding cake orders upcoming and would like to solve this problem. Thanks for your help. This site is spectacular!!!