I made a buttermilk sponge cake...it wasn't done when the timer went off, and then I left it in a bit too long. It's browner than I'd like but not burnt, I think. How can I tell if it's overbaked?
You're probably fine. The truest way to tell if a cake of over baked is if, when you slice it horizontally into layers, they break. By then it's a bit too late. That said, icing covers a multitude of sins.
Or use an overbaked cake I. Trifle or tiramisu, so it can borrow moisture from liqeuer and cream