Becca, by “one of those cake in a cups”, are you referring to cupcakes? Because they’re named as such because the earliest ones were literally just cakes baked inside of a cup instead of a cake tin.

Nowadays they’re usually made inside of a dedicated cake tin, with paper bases working as the “cup”, but you could conceivably make your own “traditional cupcakes” by buying box cake mix and using it inside of cups you intend to bake in.

Warning to anyone who decides to do this. You should make sure that your cups can take baking temperatures before you do so, and probably only half-fill the cups. Three-quarters at most, and I expect that to be too much.

I admit that I am NOT speaking from experience, just making an educated guess based on the fact that things are purposefully made in the most minimalistic manner possible nowadays.