I just used for the first time an 11x15 pan, 2 inches deep. I baked the chocolate stout cake in it, but forgot to use heating cores. The tester came out clean but it sunk in the middle. I am going to torte it when it is completely cool to make sure it is done inside. I'm thinking that if I fill it I can level it that way. Should I just start over?

Oh, and I baked it at 325 for about 55-60 minutes.

Depends on how sunk it was...If you have enough room to torte it and level it off because it only sunk a little, it should be fine. If it's only 1/2" deep in the middle, though, you might have trouble! Just go ahead and torte it to see what it looks like on the inside, but as long as it didn't sink too much you should be fine. If you don't like the look of it, you can decide whether it needs to be redone or not then.

Well, the sides rose beautifully, but I think that I either filled it too full, or overbeat it. I used bake even strips. It didnt really sink directly in the middle-but more on one side-it kind of slopes from about 2 inches in and then levels off to a normal size cake.

I am just kicking myself for not thinking about using the flower nails in it. My husband is hoping that it is a flop so that he can eat it now. This is for my father-in-law's birthday.

I torted the cake and it is done on the inside. I am going to go ahead and bake another cake and use both cakes together.