3 tablespoons Butter
3 tablespoons Flour
2 cups Milk
pinch of cayenne
1/2 tsp Kosher Salt
4 cups Sharp Cheddar Cheese grated
Preheat oven to 375 degrees F.
Melt butter in heavy saucepan over low heat. Add flour, stirring until smooth.
Cook 1 minute, stirring constantly. Gradually stir in milk and cayenne.
Cook over medium heat, stirring constantly until thickened and bubbly.
Keep warm, but do not allow to scorch.
Cut potatoes into 1/4 inch thick slices.
Layer 1/2 of potato slices, onion, salt, pepper, cheese and white sauce in order given in 2 quart casserole dish. Repeat.
Cover and place on large cookie sheet to prevent oven spills and bake for 45 minutes.
Remove cover and continue baking until knife pierces potatoes, about 15-20 minutes more.