Onion Beef Macaroni Casserole

1 ½ lb. ground beef                                                                2 cups water

1 envelope onion soup mix                                                1 cup macaroni

1 Tbsp. flour                                                                               ¼ cup grated cheese, or more to taste

1 cup tomato sauce

Preheat oven to 400°. Brown meat, pour off fat. Stir in soup mix, flour, tomato sauce and  water. Simmer covered for 5 minutes. Cook macaroni in       1 ½-quart salted water, drain. Add to meat mixture. Pour into 1 ½ quart casserole. Sprinkle with grated cheese. Bake for 15 minutes.