my carrot cake sheetcake from sinking in the middle after it comes out of the oven and tests done?
If it's still sinking, it's not done. I have one recipe that is like that - it will test done, but I have to go by the times I have worked out and not a tester or I will pull it early and it will not be salvageable. Do you ever use flower nails or a heating core in the center?
My white chocolate recipe is like that. After it tests done, I continue to bake it another 10 - 20 minutes. If you are not using baking strips or a heating core, lower the temp and increase the baking time.