Preheat oven to 350 F. Combine potatoes, onion, carrots and ham; place in 9x13" greased pan. Blend together the flour, soup, milk and pepper in a saucepan and cook, stirring constantly until the mixture boils. Pour over vegetables and ham. Cover and bake 1 hour. Remove lid and bake 30 minutes longer. Makes 8 to 10 servings.