Begin by boiling a large pot of salted water. Add the jumbo pasta shells and cook until al dente, about 8-10 minutes. Once done, carefully drain and rinse the shells under cold water to stop the cooking process. Spread them out on a clean kitchen towel to dry.

In a mixing bowl, combine the ricotta cheese, shredded mozzarella, grated Parmesan, minced garlic, a pinch of nutmeg, and Italian herbs. Mix until well combined, and season to taste with salt and pepper.

Heat a saucepan over medium heat and add a drizzle of olive oil. Sauté finely chopped onion and minced garlic until they are fragrant and translucent, about 3-4 minutes. Stir in your marinara sauce and add extra Italian herbs. Let the sauce simmer for about 10 minutes.

Grab a baking dish and spread a thin layer of the marinara sauce on the bottom. Fill each cooled pasta shell with the cheese mixture and arrange them in the dish.

Preheat your oven to 375°F (190°C). Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil, top with additional mozzarella cheese, and bake uncovered for another 10 minutes until bubbly and golden.

Once baked, let it cool for about 5 minutes. Garnish your stuffed shells with freshly chopped parsley and a sprinkle of extra Parmesan before serving.