1 onion, thinly sliced
3 tablespoons butter
3/4 cup fine bread crumbs or 2 1/2 tbsp. flour
1 tsp. salt
1 1/2 cups hot milk
Preheat oven to 400°F.
Arrange alternate layers of potatoes and onions in a buttered casserole dish. Over each layer, sprinkle bread crumbs or flour and the spices. Add salt to milk and pour over all.
Top with remaining bread crumbs and dot with butter.
Cover and bake in a preheated oven for 30 minutes, then uncover and bake until browned on top and until potatoes are tender. Add Cheese to the top and broil until melted.