Boil potatoes in lightly salted water until almost done. Drain, peel. and dice. Place in a buttered baking dish. Combine flour and butter in a saucepan over a low heat. Mix into a roux. Slowly add cream, stirring constantly. Simmer until thickened. Season with salt and pepper. Pour over potatoes, toss to coat. Cover with cheddar cheese and sprinkle with bread crumbs. Bake at 400 degrees F. (205 degrees C.) until cheese is golden brown.