1. Cook the Manicotti:

• Boil the Pasta: Cook the manicotti pasta according to the package directions, making sure to undercook it by about 2 minutes (al dente) since the pasta will cook further in the oven. Drain and set aside to cool slightly. Be careful not to overcook the pasta, or it may tear when stuffing.
• Prepare the Filling: In a large bowl, combine the ricotta cheese, 1 1/2 cups shredded mozzarella, Parmesan, egg, parsley, oregano, garlic powder, and a pinch of salt and pepper. Stir until the mixture is smooth and well combined.

2. Stuff the Manicotti:

• Using a spoon or a piping bag, carefully stuff each manicotti shell with the ricotta mixture. Fill them as much as possible without overstuffing, and place the filled shells in a greased 9×13-inch baking dish.

3. Prepare the Sauce:

• Cook the Garlic: In a small saucepan, heat the olive oil over medium heat. Add the minced garlic and sauté until fragrant, about 1-2 minutes.
• Add the Marinara: Stir in the marinara sauce, basil, and red pepper flakes (if using). Let the sauce simmer for about 5-10 minutes, allowing the flavors to meld together. Taste and adjust the seasoning with salt and pepper.

4. Assemble the Manicotti:

• Pour a generous layer of marinara sauce over the stuffed manicotti in the baking dish, making sure each shell is coated. Sprinkle with additional shredded mozzarella and Parmesan cheese on top.
• Cover and Bake: Cover the baking dish with aluminum foil and bake in a preheated oven at 375°F (190°C) for 25 minutes. Then, uncover the dish and bake for an additional 10 minutes to allow the cheese to melt and turn golden brown.

5. Serve and Enjoy:

• Once baked, remove the manicotti from the oven and let it rest for about 5 minutes before serving. Garnish with freshly chopped basil or parsley if desired. Serve with a side of garlic bread and a green salad for a complete meal.