1/4 c. butter
1 c. chopped onion
1 c. milk
1 egg
2 c. grated Cheddar cheese
1 1/2 c. Bisquick

Saute onion. Beat egg. Add milk, Bisquick, onion, 1 cup cheese. Pour into 8 inch square pan. Sprinkle last cup of cheese on top. Bake at 350 degrees for about 30 minutes.

Can be prepared ahead of time and reheated at serving time.