Vegetable Beef Casserole

3 medium unpeeled potatoes, sliced
4 carrots, sliced
4 celery ribs, sliced
2 C. fresh or frozen green beans
1 medium onion, chopped
1 lb. ground beef (cooked or raw)
1 tsp. dried thyme
1 tsp. salt
1 tsp. pepper
3 medium tomatoes, chopped
1 C. shredded cheddar cheese

In a 3 quart casserole, layer half of the potatoes, carrots, celery, green beans, and onion.  Crumble half of the beef over vegetables.  Sprinkle with 1/2 tsp. each thyme, salt, and pepper.  Repeat both layers.  Top with tomatoes.  Cover and bake at 400 for 15 minutes.  Reduce heat to 350 and bake about 1 hour longer or until vegetables are done.  Sprinkle with cheese.  Cover and let stand until cheese is melted.