01 -
Preheat oven to 350°F. Spray a 9x13-inch baking dish with nonstick cooking spray and set aside.
02 -
Heat olive oil in a large skillet over medium-high heat. Add ground beef, diced onion, salt, garlic powder, and black pepper. Cook for 8 to 10 minutes until onions are softened and beef is thoroughly cooked with no pink remaining. Drain excess grease.
03 -
In a large mixing bowl, whisk together cream of mushroom soup, whole milk, and sour cream until fully blended.
04 -
Add thawed hashbrown potatoes, cooked beef mixture, and 1 cup shredded Colby Jack cheese into the creamy base. Stir until all components are evenly combined.
05 -
Transfer the mixture into the prepared baking dish and spread evenly. Sprinkle remaining 2 cups of shredded Colby Jack cheese evenly over the top.
06 -
Bake uncovered for 35 to 40 minutes until cheese is melted and lightly browned. Remove from oven and let rest for 5 to 10 minutes to allow the sauce to set before serving.