Corn Bread Casserole

Hi - Would like to share some of my family's favorites. New to board but really enjoy all the wonderful recipes so far.

Received this recipe from a friend in Budapest, Hungary when we were stationed there back in 1988.

2 large onions, chopped
6 tablespoons butter or margarine
2 eggs
2 tablespoons milk
2 (17 ounce) cans cream style corn
2 (8 1/2 ounce) boxes Jiffy corn muffin mix
1 cup sour cream
2 cups shredded sharp Cheddar cheese

Preheat oven to 425 degrees F.

Saut