I'm so frustrated. 2 of the last 3 cakes I've baked have NOT baked properly. They've looked done. Tested done but aren't done!

On one my husband was in charge so that could have been part of the problem. But the second the center was done. but the outside bottom of the layer was still under cooked. How do I fix this? I have a thermometer in my oven. I've moved it around... it seems like the temp is the same everywhere.

I've got three 4 cakes to do in the next 10 days... if I don't figure this out I'm in big  trouble.

Any suggestions are greatly appreciated!

You could try using a flower nail in the cake. Or baking strips. If the top of my cake cooks faster than the rest, I just cover it with foil so that it won't burn. (Only have that problem with bigger cakes)

Are you baking at 350?  Try turning your oven down to 325.  I bake at 325 until it's done and I don't have to use a heating core, flower nail, baking strips or anything.