My guess would be that you are baking at too high of a temperture. I bake all of mine at 325 degrees & bake for a little longer time. Also check your oven temperture with an oven thermometer.
That's such a colorful cake and amazingly yummy!
I, too, will have issues with this so maybe I do need to turn my oven temp down. I've also never baked a non-chocolate cake in my new oven so maybe I won't have a problem?
Thanks, I'm gonna try that with my next cake.