Cut bread into 1 inch cubes. Arrange cubes in bottom of a buttered 13x9 inch baking dish. Sprinkle Swiss cheese evenly over bread.
Beat together eggs, milk and seasonings. Add onion. Pour over cheese layer.
Bake at 325° F for 25 minutes. Cook asparagus according to package directions. Drain.
Remove casserole from oven and top with asparagus. Sprinkle with Cheddar cheese. Return dish to oven and bake for 10 to 15 additional minutes.
Let stand 5 minutes before serving.Servings: 10