Crockette Macaroni & Cheese

2 cups cooked macaroni
1 tablespoon butter or margarine, melted
1 cup evaporated milk
1/2 teaspoon salt
1 cup shredded sharp process cheese
1 tablespoon minced onion

Toss macaroni with butter or margarine.
Add remaining ingredients.
Pour into lightly greased crock-ette.
Cover and cook 2 &1/2 to 4 hours, stirring once or twice.