I am really ashamed to admit this problem. I do bake cupcakes for a living, own my own company, but I am having problems with adding fruit to my cupcakes. They come out beautifully, risen like they should, fluffy, they look moist, but then the problem comes. As they cool down, still in the pan, they fall and shrink. They end up pulling away from the paper. They are smaller than the rest of my cupcakes. They sink in the middle. I bake them longer than my other cupcakes, thinking that they are not done in the middle. Can someone please help me with the great problem for me?
I'm not sure but maybe the fruit is adding more liquid to the batter so there is less structure causing the cakes to sink afterwards, so maybe add a bit more flour to your recipe and see if that helps.
try covering your fruit in a light dusting of flour before you put it in the batter that is what i always do and it works great