Preheat your oven to 375°F (190°C). Grease a 9x13-inch casserole dish with butter or cooking spray.

In a large skillet over medium heat, brown the ground beef, breaking it up as it cooks. After about 5 minutes, add the diced onion and continue cooking until the beef is fully browned and the onion is softened.

Season with salt, pepper, and any optional spices like garlic powder or paprika. Drain any excess fat from the pan.

Stir the cream of mushroom soup and sour cream into the beef mixture. Let it cook for 2–3 minutes, stirring often, until everything is heated through and well combined.

Spread the beef mixture evenly into the prepared casserole dish.

Sprinkle 1 cup of shredded cheddar cheese over the beef mixture.

Arrange the tater tots in a single layer over the cheese, covering the entire surface.

Bake the casserole for 25–30 minutes, or until the tater tots are golden brown and crispy.

Remove the casserole from the oven. Sprinkle the remaining 1 cup of cheddar cheese over the top.

Return to the oven for another 5 minutes, or until the cheese is melted and bubbly.

Let the casserole rest for 5 minutes before serving. This helps it set up and makes it easier to slice. Enjoy!