Step 1: Preheat oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish.
Step 2: In a large skillet, brown the ground meat over medium-high heat. Break it apart with a spoon as it cooks. Once no pink remains, drain any excess fat.
Step 3: Return the drained meat to the skillet. Add chopped onion and bell pepper (if using). Cook for 5-7 minutes, or until vegetables are softened. Season with salt, pepper, garlic powder, and onion powder.
Step 4: In a large mixing bowl, combine the condensed soup, milk, and sour cream. Whisk until smooth.
Step 5: Add the cooked meat and vegetable mixture to the soup mixture. Stir thoroughly until everything is evenly coated.
Step 6: Pour the entire mixture into the prepared baking dish and spread evenly.
Step 7: Sprinkle 1 cup (half) of the shredded cheese evenly over the meat mixture.
Step 8: Arrange the frozen tater tots in a single layer over the cheese, covering the entire surface of the casserole.
Step 9: Cover the baking dish loosely with aluminum foil. Bake for 30 minutes.
Step 10: Remove the foil. Sprinkle the remaining 1 cup of shredded cheese over the tater tots. Return the dish to the oven and bake, uncovered, for another 20-25 minutes, or until the tater tots are golden brown and crispy, and the cheese is melted and bubbly.
Step 11: Remove from oven and let the casserole rest for 5-10 minutes before serving. Garnish with fresh chopped parsley or green onions, if desired. Enjoy your delicious Easy Cheesy Tater Tot Casserole!