Creating the Easy One-Pan Beefy Tortellini Bake is simple and straightforward. Just follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C).
2. Cook the Beef: In a large oven-safe skillet or pan, brown the ground beef over medium heat. Break it up into small pieces while cooking, and season with salt, pepper, Italian seasoning, and garlic powder.
3. Add the Marinara Sauce: Once the beef is browned and cooked through, pour the marinara sauce over it. Stir well to combine.
4. Incorporate Tortellini: Add the refrigerated tortellini directly to the skillet, mixing gently to coat them with the sauce.
5. Top with Cheese: Sprinkle the shredded mozzarella and grated Parmesan cheese evenly over the tortellini.
6. Bake: Transfer the skillet to the preheated oven and bake for 15-20 minutes or until the cheese is bubbly and golden brown.
7. Garnish: Remove from the oven and let it cool for a few minutes. Garnish with fresh basil if desired.
8. Serve: Spoon portions onto plates, and enjoy!

Through these systematic steps, you can effortlessly whip up this enticing dish in no time.