Set your oven to 375°F (190°C). Lightly grease your baking dish with oil or spray to prevent sticking. This gives your tater tots the perfect golden crust.
Heat your skillet over medium heat and add the ground beef or lamb. Break it apart with a spoon while cooking. Add the chopped onion and garlic. Sauté until the onion is soft and translucent. Drain any excess grease for a cleaner dish.
Add the cream of mushroom soup, beef broth, frozen vegetables, Worcestershire sauce, thyme, salt, and pepper. Stir everything together well. Let it simmer for 5 minutes. This gives the filling time to thicken and soak up flavor.
Spoon the meat and veggie mixture into your prepared baking dish. Spread it out evenly. Arrange frozen tater tots in a single layer on top. Keep them spaced out a little so they crisp up nicely.
Pop the dish into the oven and bake for 25–30 minutes. The tots should turn golden brown and crispy on top. This is where the magic starts to happen.
Once the tots are crisp, sprinkle shredded cheddar cheese all over the top. Return the dish to the oven for another 5 minutes or until the cheese melts and gets bubbly.
Take it out, let it cool for 5 minutes, and sprinkle chopped parsley over the top if you like. It adds a fresh finish and brightens up the dish.