Preheat oven to 400 degrees. Grease pie plate, 10x1 1/2, or square baking dish, 8x8 inches. Cook and stir the ground beef and onion in 10 inch skillet until beef is brown; drain. Stir in seasoning mix. Spoon into pie plate.
Beat baking mix, milk and eggs about 1 minute with wire whisk or hand beater or til almost smooth. Pour into pie plate. Bake about 25 minutes or til knife inserted in center comes out clean. Sprinkle with cheese. Bake about 2 minutes longer or til cheese is melted. Cool 5 min. Garnish with lettuce, tomatoe and olives.
FOR 1/2 RECIPE: Use 1 quart square or round casserole. Decrease baking mix to 1/2 cup, milk to 3/4 cup, and eggs to 2. Divide remaining ingredient amounts in half. Decrease beat time to 10 seconds in blender or 30 seconds with wire whisk or hand beater.