Preheat Your Oven: Set your oven to 375°F (190°C).
Cook the Beef: In a large skillet over medium heat, cook the ground beef and diced onion until the beef is browned and fully cooked. Drain any excess grease.
Prepare the Sauce: Add the cream of mushroom soup, milk, garlic powder, salt, and pepper to the skillet. Stir until well combined. If using frozen mixed vegetables, stir them in at this stage.
Assemble the Casserole: Spread the beef mixture evenly into a 9x13-inch baking dish. Sprinkle 1 cup of shredded cheddar cheese over the top.
Add the Tater Tots: Arrange the tater tots in a single layer over the cheese.
Bake: Bake in the preheated oven for 30 minutes. Remove from the oven, sprinkle the remaining cheese over the tater tots, and return to the oven for an additional 10-15 minutes, or until the cheese is melted and bubbly.
Serve: Let the casserole cool slightly before serving. Enjoy!
