Variation on Yard's Pastry Cream Cookies

I made these using Yard's recipe from The Secrets of Baking, except I used chocolate muffin crumbs instead of cake crumbs, chocolate pastry cream instead of plain pastry cream, and Kahlua instead of rum. If your dough is too thin, just stir in a little flour until it's thick enough to hold its shape on the baking sheet. I think I used about 1/2C crumbs plus maybe 1-2T AP flour. They are dense and moist and have a nice hazelnut flavor.