Spray pan with non-stick spray. Tear apart 2 slices of bread and put in the bottom of a 9x13 pan. Cook sausage with onion over med heat until browned and layer in 9x13 pan. In a seperate bowl whip up eggs with 2 cups of milk and 1/2 tsp salt. Pour egg mixture over top of sausage and then sprinkle cheese on top. Cook for 30 min at 350 until browned and bubbly.