Beef with cheddar

2 TBSP vegetable oil , divided Didn't use this 1 lb lean ground beef I used about a pound and a half 2 onions finely chopped I used much less 4 stalks celery[...]

1 1/2 lbs ground beef 1 (16 ounce) can green beans 1 (10 1/2 ounce) can tomato soup 1 medium onion , chopped 1 1/2 cups mashed potatoes (may substitute 1[...]