I have a recipe for a coconut cake that tastes great but sinks in the middle every time I bake one (13 x9). It's made with a reg. white cake mix, 1/4 tsp. baking powder, 1/2c oil, 3 eggs, (I've used the whole egg and just the whites and it made no difference), 1c sour cream, 81/2 oz. cream of coconut. It bakes for 30-40 minutes in a 350F oven.
Anyone have any suggestions or changes I could make to correct this problem?
Kathy