Preheat the Oven: Preheat your oven to 375°F (190°C). Grease a 9x9-inch baking dish with cooking spray or butter.
Layer the Tater Tots: Spread the leftover tater tots evenly across the bottom of the greased baking dish. This will serve as the base of your casserole.
Prepare the Meat Mixture: In a large skillet, cook the chopped onion over medium heat until softened and translucent, about 5 minutes. If you’re using ground meat, you can add it to the skillet and cook until browned. If you’re using pre-cooked meat like ham, shredded chicken or sausage, simply warm it through.
Combine the Sauce: In a large bowl, combine the cream of mushroom soup, sour cream, milk, garlic powder, onion powder, smoked paprika, salt, and pepper. Mix until smooth.
Stir in half of the shredded cheese and the cooked meat mixture.
Add Vegetables: Fold in the frozen peas and carrots (or your preferred vegetables) to the mixture.
Assemble the Casserole: Pour the meat and vegetable mixture over the layer of tater tots in the baking dish. Spread it evenly with a spatula to ensure it covers the tots.
Top with Tater Tots: Arrange another layer of leftover tater tots on top of the casserole. Sprinkle it with remaining cheese.
Bake: Cover with foil and place the casserole in the preheated oven and bake for 25 minutes. Then, remove foil and bake for an additional 10 minutes until golden brown and bubbling.
Garnish and Serve: Once done, remove the casserole from the oven and let it cool for a few minutes. If desired, garnish with chopped parsley for a fresh touch. Serve warm and enjoy!