Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Arrange the frozen tater tots in a single layer on the prepared baking sheet. Bake for 15-20 minutes or until golden and crisp, flipping halfway.
While the tots bake, cook the ground beef in a large skillet over medium heat. Add the chopped onion and a pinch of salt and pepper. Cook until the beef is browned and the onion is soft, about 6-8 minutes. Drain excess grease if needed.
Stir in ketchup and mustard for classic cheeseburger flavor, then turn off the heat.
Remove tater tots from the oven and let them cool slightly. To shape the cones: use a muffin tin, lining each cup with tater tots to create a cone shape, layering and pressing them firmly together. Return to oven and bake for 10 more minutes to set the shape.
Meanwhile, mix the cooked beef mixture with the crumbled bacon, cheddar cheese, and mozzarella cheese.
Spoon the cheeseburger filling into each tater tot cone, pressing gently to pack.
Sprinkle extra cheese or bacon on top if desired, then return to the oven for 5 minutes, or until the cheese is bubbly and melted.
Carefully loosen cones from the muffin tin and serve hot, topped with your favorite burger fixings.
Notes
Store any leftover cones in an airtight container in the refrigerator for up to 3 days. To reheat, place cones on a baking sheet in a 350°F oven for 10-15 minutes, or until hot and re-crisped.