This recipe (well, more like a tip) came about quite by accident.
One cake mix (chocolate, yellow, white) or other layer cake recipe
A small jar of jam (strawberry and raspberry are my favorites)
One recipe vanilla buttercream frosting
Prepare the cake using the two-layer method.
Cool.
Spread the jam on top of layer cake one, stopping about a half-inch from the sides.
Place layer cake two on top, wiping away any jam that oozes out (it makes it harder to frost.)
Frost the whole thing.
If you aren't going to be serving soon, you may wish to spread a little frosting on the top of layer one and bottom of layer two to keep the jam from seeping into the cake too much (and thus, tumbling over.)