40 oz. frozen hash brown potatoes, thawed
1 1/2 c. milk
2/3 lb. Velveeta cheese
8 oz. grated cheddar cheese
2 sticks butter

Heat milk, cheeses and butter over very low heat until melted. Pour cheese mixture over thawed potatoes. Let stand at least 1 hour before baking. Do not stir. Bake 1 hour at 350 degrees in a 9 x 13 pan.