Impossible Cheeseburger Pie
["1 lb. ground beef", "3 medium onions, chopped", "1/4 tsp. salt", "1/4 tsp. pepper", "1 1/2 c. milk", "3 eggs", "3/4 c. Bisquick original baking mix", "2 medium tomatoes, sliced", "4 (1 oz.) slices Cheddar or American cheese"]
["Heat oven to 400\u00b0.", "Grease pie plate.", "Cook ground beef and onions, stirring frequently until beef is browned; drain.", "Stir in salt and pepper.", "Spread in pie plate.", "Beat milk, eggs and baking mix in blender on high speed about 15 seconds or with wire whisk or hand beater about 1 minute, until smooth.", "Pour over beef mixture. Bake 25 minutes.", "Top with tomatoes and cheese.", "Bake 5 to 8 minutes longer or until knife inserted in center comes out clean. Cool 5 minutes."]
["ground beef", "onions", "salt", "pepper", "milk", "eggs", "Bisquick original baking mix", "tomatoes", "Cheddar"]