In melted butter, saute onions and bell pepper for 1 minute.
Add seasonings and flour.
Blend in milk, stirring until thick.
Add potatoes and 1 cup sharp cheese.
Stir until cheese is melted.
Pour into 3-quart flat casserole.
Spread remaining cheese on top.
Bake at 350 degrees for 30 to 40 minutes or until bubbly.