Preheat and Prep: Preheat your oven to 375°F (190°C). Grease a $9times13$-inch baking dish with non-stick cooking spray.
Brown the Beef: In a large skillet over medium heat, cook the ground beef until it is no longer pink, breaking it up with a spoon as it cooks. Drain any excess fat.
Sauté Aromatics: Add the minced garlic and diced onion to the skillet with the cooked beef. Cook for an additional 2 to 3 minutes until the onion is soft and translucent, then stir in the can of cream of mushroom soup.
Layer the Base: Spread the beef and mushroom soup mixture evenly across the bottom of your prepared baking dish.
Add Cheese Layer: Sprinkle half of the shredded cheddar cheese evenly over the beef layer.
Arrange Tots: Arrange the frozen tater tots in a single, neat layer right over the cheese.
Mix the Sauce: In a small bowl, whisk together the sour cream, garlic powder, salt, and pepper. Gently spread or dollop this mixture evenly over the tater tots.
Top with Cheese: Sprinkle the remaining shredded cheddar cheese over the top.
Bake Covered: Cover the baking dish tightly with aluminum foil and bake in the preheated oven for 30 minutes.
Crisp It Up: Remove the foil and bake for an additional 10 to 15 minutes, or until the cheese is melted and bubbly and the tater tots turn golden brown and crispy.
Cool and Serve: Let the casserole rest for a few minutes before serving so the layers set. Enjoy!