Brown the ground beef with the diced onion.
Boil potatoes until tender.
Once potatoes are cooked, drain and mash.
Drain fat from ground beef. Return to the frying pan, return to low heat and add about a cup of BBQ sauce. Simmer.
Put in the bottom of your casserole dish.
Top ground beef with potatoes making sure to cover all the ground beef bottom.
sprinkle a little Parmesan cheese, a little cheddar cheese and some bacon bites over the top
Broil on low until the cheese melt and the potato goes golden.