Whenever I bake a cake in my Aga four oven cooker, the center of the cake sinks in after about five minutes of cooling. I did not have this problem in my conventional oven. I have tried leaving the cake in longer, covering with the cold rack etc. Nothing seems to work. I think I need to put another oven in my kitchen. The Aga is just not that great for baking, at least for me. Does anyone have any other suggestions? This last time I used duck eggs in the cake, but have had the same experience with chicken eggs. Thank you in advance for any input.