Have you ever tried putting jam in your cupcakes? Simply half fill one of your cupcake cases, that's been placed in a cupcake tray, with your cake mix and then put a generous dollop of a jam/fruit conserve of your choice and then cover with mix and bake.
Be careful the jam will be very hot, so wait a couple of minutes at least. Maybe cut in half to speed up cooling or add ice cream or cream. Yummy! Or even custard if you want to keep it nice and hot!