Brown ground beef until cooked through. Drain.
Return to skillet, add in onions and saute 2-3 minutes.
Add in ketchup, mustard, and 1 cup of cheese. Stirring until heated through. Remove from heat. Salt and pepper to taste.
Grease a 9×13 baking dish, or coat with non stick spray.
Lay crescent rolls out flat to cover the bottom of the dish like a crust. Press seams together so there aren’t any gaps.
Spread hamburger mixture evenly over the crescent rolls.
Top evenly with tater tots.
Bake uncovered at 350 degrees for 35-40 minutes or until tater tots are done.
Remove from oven and sprinkle the remaining cup of cheese over the top of the casserole.
Return to oven cooking 5 more minutes, or until the cheese is melted.
Let the casserole cool for 5 minutes before serving.