Heat oven to 400 degrees. Grease 10-inch pie plate. Brown beef and onion; drain. Stir in salt and pepper. Spread in the plate. Beat milk, baking mix, and eggs 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
Yield: 6 to 8 servings