Does anyone know why my cupcakes bake up big and beautiful but then seem to shrink upon cooling? I bake them at 350 for 20 minutes as directed and a toothpick inserted comes out clean before taking out of oven.[/url]

are you cooling them in the pan or removing them? If you let them cool in the pan the pan is hot and will continue to bake them.... so they're getting over baked and shrink up.

There are some other possiblities too, but this seems to be the most common

I agree with Leily - it's overbaking, either in the oven or in the pan with "carry-over" cooking.

wow..I never knew. Yes, I do cool them in the pan and possibly in the oven too. How long do you bake your cupcakes for?

Well, there are variables such as what size cupcakes and sometimes the recipe itself, but TYPICALLY, approx. 20 minutes for cupcakes. All products, whether baked or cooked if left in/on pan have what is called carry-over cooking. Meaning, the pan is still hot and so, it continues to cook beyond removing it from the heat source. Hope this helps.

Using too much egg and/or whipping too much air into the batter can cause them to deflate as well.

Don't forget that a cake, when baked properly, will shrink away from the pan also. Same is true for cupcakes. This may be something you simply cannot control.