1 lb. hamburger
1/2 c. chopped onion
1 env. taco seasoning mix
1 1/4 c. milk
3/4 c. Bisquick
3 eggs
2 tomatoes, sliced
1 c. shredded cheese

Heat oven to 400 degrees. Grease a pie plate. Cook and stir meat and onion until meat is lightly browned. Drain off any excess fat, then stir in taco seasoning. Spread in pie plate. Beat together milk, eggs, and Bisquick until smooth. Pour over meat layer and bake 25 minutes. Top with tomatoes and cheese and bake just until knife inserted in center comes out clean, about 8 to 10 minutes. Cool 5 minutes before cutting into wedges.