Preheat the Oven:
Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish or casserole dish with cooking spray or butter.

Cook the Ground Beef:
In a large skillet, heat a tablespoon of oil over medium heat. Add the ground beef and cook until browned, breaking it apart with a wooden spoon as it cooks (about 6-8 minutes). Drain excess fat, if necessary. Add the chopped onion and minced garlic, and sauté for another 2-3 minutes until the onion becomes soft.

Make the Casserole Mixture:
Stir in the cream of mushroom soup, sour cream, milk, Worcestershire sauce, salt, and pepper. Cook for another 2-3 minutes, stirring occasionally, until everything is combined and heated through. Remove the skillet from the heat.

Add the Cheese:
Stir in the shredded cheddar cheese until it melts and combines with the creamy beef mixture. Taste and adjust seasoning as needed.

Assemble the Casserole:
Pour the beef and cheese mixture into the prepared casserole dish and spread it out evenly. Top the beef mixture with the frozen tater tots in a single layer. Arrange them neatly across the top.

Bake the Casserole:
Bake in the preheated oven for 25-30 minutes or until the tater tots are golden brown and crispy. The cheese should be bubbly, and the casserole should be heated through.

Serve:
Let the casserole sit for about 5 minutes before serving. Garnish with chopped green onions or parsley for extra color and flavor.