Biscuit Topped Hamburger Stew

1 lb hamburger
1/2 cup chopped onion
1 (14 oz )can diced tomatoes undrained
1 (12 oz) jar beef gravy
1 1/2 cups peeled diced potatoes
1 cup frozen cut carrots
1 cup frozen cut green beans
salt and pepper to taste
1 small can refrigerated biscuits

Cook ground beef and onion and drain. Add together all remaining ingredients except the biscuits. Bring to a boil and cook 10 minutes till veggies are tender. Add cooked beef and onions. Pour into an ungreased 8" square pan. Separate biscuits into 5 biscuits; cut each in half. Arrange cut side down around the outside edge. Bake @ 375 for 20 minutes or till biscuits are golden