Brown ground beef and onion. I used 2lbs of lean ground beef and 1 large onion.
In separate bowl mix 1 can cream of mushroom soup, 1 cup sour cream and 1/2 cup milk.
Mix well and spread on top of the ground beef.
Place frozen tater tots on top of meat and soup/sour cream layer.
After baking for 45 minutes remove from oven and sprinkle with shredded sharp cheddar cheese. Use as much cheese as you like. Return to oven and bake for 10 more minutes.