Sorry the picture isn't that clear but I took it from my ipad since it was handy.. This recipe is from Better Homes and Garden Holiday magazine.
Non-stick cooking spray
2 pounds of sweet potatoes (3 medium), peeled - or any other potatoes you prefer.
2 tablespoons butter
2 tablespoon all purpose flour
1 1/2 cup half and half, light cream or milk
1 cup shredded Fontina cheese (4 ounces)
1 tablespoon fresh thyme leaves or 1 teaspoon dried thyme, crushed
1/4 teaspoon salt
1/8 teaspoon ground pepper
Preheat oven to 350 degrees. Lightly coat a 2 x 2 1/2 quart baking dish with cooking spray; set aside. Using a sharp knife or a mandoline, cut sweet potatoes lengthwise into 1/4 inch thick slices. Set aside.
For sauce, in a medium saucepan melt butter over medium heat. Stir in flour; cook and stir for 1 minute. Stir in half and half. Cook and stir until thickened and bubbly; cook and stir for 1 minute more.
Reduce heat to low. Add 3/4 cup of the cheese, stirring until cheese is melted. Stir in thyme, salt, and pepper.
Place potatoes slices in the prepared baking dish. Pour sauce over potatoes; sprinkle with the remaining 1/4 cup cheese.
Bake, covered, about 50 minutes or until potatoes are tender. Bake uncovered, about 20 minutes more or until edges are brown. Let stand for 15 minutes before serving.