1. Prepare the Pasta Shells: Bring a large pot of salted water to a boil. Cook the jumbo pasta shells until slightly under al dente, as per the package instructions. Drain and rinse them briefly with cold water to stop the cooking process and prevent sticking.
2. Cook the Ground Beef and Sauce: Heat a tablespoon of olive oil in a skillet over medium heat. Sauté chopped onions and minced garlic until fragrant. Add the lean ground beef and season with salt, Italian seasonings, onion powder, and garlic powder. Cook until browned, then stir in the marinara sauce and let it simmer for a few minutes.
3. Prepare the Ricotta Filling: In a mixing bowl, combine ricotta cheese, a beaten egg, shredded mozzarella, grated Parmesan, Italian seasonings, and a pinch of salt. If desired, add thawed and squeezed spinach for additional flavor and nutrients. Mix well to create a creamy filling.
4. Preheat the Oven: Set the oven to 350°F for baking.
5. Assemble the Stuffed Shells: Spread a thin layer of meat sauce on the bottom of a large baking dish. Use a spoon to fill each cooked pasta shell with about 2 tablespoons of the ricotta mixture. Arrange the stuffed shells side by side in the dish over the sauce layer.
6. Top with Sauce and Cheese: Pour the remaining meat sauce evenly over the stuffed shells, ensuring all are well-covered. Sprinkle with an additional layer of mozzarella and Parmesan cheese.
7. Bake the Dish: Cover the baking dish with foil to avoid over-browning the cheese. Bake the shells for 25-30 minutes or until the cheese melts and the dish is bubbly.
8. Garnish and Serve: Remove from the oven, let it cool slightly, and garnish with fresh parsley before serving. Pair with a green salad or crusty garlic bread for a complete meal.
9. Store Leftovers: Cool leftovers completely, then refrigerate in an airtight container for up to three days or freeze for up to two months. Reheat in the oven at 350°F for best results.
10. Experiment with Variations: Incorporate vegetables like spinach, explore different cheese options like smoked mozzarella, or substitute the ground beef with turkey, chicken, or mushrooms for a personalized twist.