Creating Hearty Cowboy Casserole is straightforward if you follow these easy steps:

1. Preheat your oven to 350°F (175°C).
2. Brown the Beef: In a large skillet over medium heat, brown the ground beef with the diced onion until the beef is cooked through. Drain any excess fat.
3. Mix Ingredients: In the skillet, add the frozen mixed vegetables, cream of mushroom soup, cream of chicken soup, garlic powder, onion powder, salt, and pepper. Stir until well combined and heated through.
4. Layer the Casserole: Pour the beef and vegetable mixture into a greased 9×13 inch baking dish. Spread evenly.
5. Add Cheese: Sprinkle shredded cheddar cheese evenly over the beef and vegetable mixture.
6. Top with Tater Tots: Layer the frozen tater tots on top of the cheese, arranging them in a single layer for even cooking.
7. Bake: Place the casserole in the preheated oven and bake for 40-45 minutes until the tater tots are golden brown and crispy.
8. Garnish: Remove from the oven and let it sit for a few minutes. Garnish with fresh parsley if desired.
9. Serve: Spoon the casserole onto plates and serve warm.

Following these steps will lead you to a mouthwatering Hearty Cowboy Casserole that everyone will love.