1. Cook the Pasta Shells

1. Boil a large pot of salted water.
2. Add the pasta shells and cook until al dente (slightly undercooked).
3. Drain and rinse with cold water.
4. Spread the shells on a baking sheet to cool.

2. Prepare the Beef Filling

1. Heat a skillet over medium heat and cook the ground beef until browned.
2. Drain excess fat.
3. Season with salt, pepper, garlic powder, and Italian seasoning.

3. Make the Cheese Mixture

1. In a large bowl, mix:
   • 1 cup ricotta cheese
   • 1 egg
   • 1/2 cup grated Parmesan cheese
   • Optional: spinach, garlic, or onion.
2. Stir in the cooked ground beef until well combined.

4. Assemble the Stuffed Shells

1. Preheat oven to 350°F (175°C).
2. Spread 1 cup of marinara sauce on the bottom of a 9×13-inch baking dish.
3. Fill each shell with the beef and cheese mixture using a spoon or piping bag.
4. Arrange the filled shells in the dish.
5. Pour the remaining marinara sauce over the shells.
6. Sprinkle shredded mozzarella cheese on top.

5. Bake

1. Cover the dish with foil and bake for 20 minutes.
2. Remove the foil and bake for an additional 10-15 minutes, until the cheese is bubbling and golden.