I have no idea about the store... Which castle pan? Welcome to CC!
I have the castle pan. I used a buttermilk pound cake recipe. Then I took my oversized cake plate, covered it in ground up sugar cookie crumbs. Put the cake on top of them. Then I sprinkled the cake and crumbs with a mixture of powered sugar and cinnamon. I made shells with white and chocolate candy melts swirled together in the molds. Placed them all around the cake.
People at work loved it. Not overly sweet. In fact, one lady like it so much that I am making one for her son's wedding rehearsal. I will put in on top of a larger cake.