- 5-6 large Vidalia (sweet salad) onions
- 1/3 cup butter
- 2 tablespoons all-purpose flour
- 1 teaspoon mustard powder
- 1/2 teaspoon pepper
- 1 cup milk
- 1/2 cup grated cheddar cheese
- 1 cup bread crumbs
Preheat oven to 375 degrees. Thinly slice onions to equal 4-5 cups. In a large skillet, melt 3 tablespoons of the butter. Add the onions and sauté until soft, stirring occasionally. Remove from heat.
In a saucepan, melt 2 tablespoons of the remaining butter and stir in the flour, mustard, and pepper. (This is called a "roux".)
Slowly stir in the milk and cheese. Cook until thickened. Spoon alternate layers of the onions and sauce into the baking dishes.
Sprinkle the top with the bread crumbs and dot with the remaining butter. Either bake and serve, or, cover and freeze.