Begin by bringing a large pot of salted water to a boil. Add the large pasta shells and cook according to package instructions until al dente. Drain the shells and set them aside to cool slightly.
In a large skillet over medium heat, add 1 tbsp of olive oil. Once hot, add the diced onion and red pepper. Sauté for about 3-4 minutes until the onion is translucent. Add the minced garlic and cook for another minute until fragrant.
Push the veggies to one side of the skillet and add the ground beef. Cook until browned, breaking it up with a spatula as it cooks, about 6-7 minutes. Season with salt, pepper, parsley, and oregano. Stir to combine all the ingredients.
In a mixing bowl, combine the ricotta cheese, grated Parmesan cheese, and a pinch of salt and pepper. This creamy mixture will serve as the heart of your stuffed shells.
Preheat your oven to 375°F (190°C). In a baking dish, spread 1 cup of pasta sauce on the bottom. Take each cooked shell and fill it generously with the beef and vegetable mixture, followed by a spoonful of the ricotta cheese mixture. Place the stuffed shells in the baking dish, open side up.
Once all shells are stuffed, pour the remaining pasta sauce over the top, ensuring all shells are covered. Sprinkle the mozzarella cheese evenly over the sauce.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Once baked, remove from the oven and let cool for a few minutes. Garnish with fresh basil leaves before serving. Enjoy your delicious Cheesy Italian Stuffed Shells with Ground Beef Filling!
