Tater Tot Casserole

1 pound ground beef
1 medium onion, chopped
1 (10 3/4-ounce) can cream of celery soup
1 (10 3/4-ounce) can cream of mushroom soup
1 (2-pound) bag onion-flavor Tater Tots
2 cups shredded mild cheddar cheese

Brown the beef and onion in a skillet. Add both cans of soups. In a 1 1/2-quart casserole, layer about half of the Tater Tots, half of the beef mixture, the rest of the Tater Tots, then the rest of the beef mixture. Sprinkle cheese on top. Bake at 375° until browned, about 45 minutes