Preheat your oven to 375°F (190°C).
In a large skillet, cook the ground beef and diced onion over medium heat until the meat is browned and the onion is soft.
Drain any excess grease, then stir in the cream of mushroom soup, sour cream, and 1 cup of the cheddar cheese. Season with salt and pepper.
Spread the beef mixture evenly in a 9x13-inch baking dish.
Layer the tater tots on top in a single, proud row (or toss 'em in if you’re feeling rebellious).
Bake uncovered for 35 minutes. Then sprinkle the remaining cup of cheese on top and bake for another 10 minutes until melty and golden.
Garnish with parsley if you're feeling fancy. Dig in while it’s hot and gooey.