For cheese sauce: in saucepan, melt 2 tablespoons butter. Blend in flour and cook for 1 minute. Gradually stir in milk; cook, stirring constantly until thickened. Remove mixture from heat. Add salt, pepper and cheese; let cool slightly.

Step 2

Meanwhile, in large skillet, in remaining 1 tablespoon of butter or margarine; cook bacon and mushrooms until golden brown. Add green onion and eggs. Cook over medium heat until eggs are soft scrambled. Stir cheese sauce into eggs. Pour egg mixture into a lightly greased 9x13-inch baking pan.

Step 3

For the topping: In another small bowl, combine 1/4 cup melted butter and cornflake crumbs. Sprinkle cornflakes over egg mixture. Refrigerate eggs 8 hours or up to overnight.