Impossible Cheeseburger Pie

1 lb ground beef
1 c chopped onion
1/2 tsp salt
1 c shredded cheddar cheese
1 c milk
1/2 c Bisquick baking mix
2 eggs

Heat oven to 400°. Grease 9" pie plate. Cook ground beef and onion until beef is brown; drain. Stir in salt. Spread in plate; sprinkle with cheese.
Stir remaining ingredients with fork until blended. Pour into plate.
Bake 25 minutes or until knife inserted in center comes out clean. 8 servings.