Heat oven to 400°. Grease pie plate, 10 x 1-1/2 inches. Cook and stir beef and onion over medium heat until beef is brown; drain. spread in plate. Beat milk, baking mix, eggs, salt and pepper until smooth, 15 seconds in blender on high or 1 minute with hand beater. Pour into plate. Bake 25 minutes. Top with tomatoes; sprinkle with cheese. Bake until knife inserted in center comes out clean, 5 to 8 minutes. Cool 5 minutes. Serves 6-8. brunch 05