Leftover, stale danish pastry makes a great breakfast casserole. Slice and lay in a pan (can overlap if necessary). Pour over a batter of eggs, milk,vanilla and cinnamon, a french toast batter. Refrigerate overnight or allow to soak for a bit. Then bake in 350 degree oven until puffy and golden. Dust with powdered sugar to serve.
Reheat your doughnut using an electric grill to make an almost stale donut taste great. This is a page about making grilled glazed doughnut.