Sweet Potato Au Gratin

Tasty sweet potatoes Au gratin

3 lbs sweet potatoes, peeled and cut into 1/4" slices
1/4 cup butter
1/4 cup flour
1 tsp. salt
1/4 tsp. pepper
2 cups half and half
1 1/4 cup grated Gruyere cheese
freshly grated nutmeg

Heat oven to 375.  Butter 2-3 quart baking dish and layer sweet potato slices in the dish.
In a 1 quart saucepan melt the butter, then add the flour.  Cook and stir till smooth and bubbly.  Add the salt, pepper, Gruyere and then gradually add the 2 cups of half and half while stirring.  Stir and cook till the mixture thickens then pour over the sweet potatoes.  Grate the nutmeg over the top, cover and bake for 40 minutes, or until sweet potatoes are tender.  Remove cover and bake 30-40 minutes or until your dish is a golden brown.  When I removed the lid, I sprinkled about a 1/4 cup of cheese over the top of the potatoes. 
Adapted from Betty Crocker best loved Christmas recipes.