To guarantee success with this recipe, you'll need to make sure your cakes come out of their mini bundt pans without sticking. Even when using good quality non-stick pans, it's a good idea to create another non-stick barrier with butter and flour. The best tool to spread the butter in all the little nooks and crannies of the pan is a silicone pastry brush. Try using very soft or melted butter to brush the inside of the pans, including the center column. Then dust with flour (gluten-free, of course) and shake off the excess.