Preheat your oven to 375°F (190°C).

Grease a 9x13-inch baking dish with butter or cooking spray.

In a skillet over medium heat, warm the olive oil. Add the ground beef and onion, cooking until the meat is browned and the onion is soft.

After the beef is browned, add the minced garlic, salt, and black pepper. Cook for about 1-2 minutes until fragrant.

Drain any excess fat if necessary.

Add the cream of mushroom soup, milk, and frozen mixed vegetables to the skillet. Stir until combined and creamy.

Pour the beef mixture into the greased baking dish. Sprinkle half of the shredded cheese over the top.

Arrange the frozen tater tots in a single layer over the cheese.

Bake for 30-35 minutes, or until the tater tots are golden brown and crispy.

Remove the casserole and sprinkle the remaining cheese on top, then return to the oven for an additional 5 minutes.

Let the casserole cool for a few minutes before serving hot with sides.