Tillie's Cheese Potatoes Recipe

6 large russet potatoes
1 stick butter or margarine
2 large onions
1/2 cup all-purpose flour
4 cups cold milk
1 pound Velveeta cheese, cubed
Salt and pepper

1. Boil potatoes until easily pierced with a fork. Cool and peel. Cut into bite-size chunks.
2. Preheat oven to 350F.
3. In a large saucepan, melt butter over medium heat. Add onions; cook until translucent.
4. Sprinkle flour over onions and stir until butter is absorbed. Do not brown. Add cold milk, stirring briskly with a whisk so flour does not lump. Add cheese and continue stirring until all cheese is melted and sauce has thickened.
5. Add potatoes and stir well. Spoon into a 13-by-9-inch casserole dish. Bake 30 minutes. Serveds 6 to 8.