01 - Preheat the oven to 375°F.
02 - In a large skillet over medium heat, cook ground beef with chopped onion and minced garlic. Season with salt and black pepper. Drain excess fat if needed.
03 - Add cream of mushroom soup, milk, and frozen mixed vegetables to the cooked beef. Stir well and cook for 2 to 3 minutes, allowing the mixture to combine and warm through.
04 - Transfer the beef and vegetable mixture into a greased 9x13-inch baking dish.
05 - Arrange frozen tater tots evenly over the filling in a single layer.
06 - Bake uncovered for 35 to 40 minutes, until tater tots are golden and crisp.
07 - If using shredded cheddar cheese, sprinkle over the top during the last 5 minutes of baking and return to the oven until melted.
08 - Allow the hotdish to rest for 5 minutes before serving.