The best stuffed shells

Ingredients:

Marinara sauce

• 1/4 cup olive oil
• 1 small onion, diced
• 3 cloves garlic, crushed
• A pinch of crushed red pepper flakes, optional
• 1/4 cup tomato paste
• 2 x 800g cans of good quality whole peeled plum tomatoes, pureed
• 1 sprig of basil
• 2 tsp dried oregano

Shells and filling

• 250 g large shell pasta
• 2 cups whole milk ricotta
• 220 g grated semi-skimmed mozzarella
• 3 tbsp grated Parmesan cheese + extra for sprinkling
• 1/4 cup finely chopped flat-leaf parsley leaves
• 1 large egg, lightly beaten

Preparation:

1. Marinara sauce:
   
   Heat oil in a medium heavy-bottomed saucepan over medium heat. Add the onion and cook, stirring occasionally, until softened, 8–10 minutes. Add the garlic and red pepper flakes, if using, and continue cooking, stirring occasionally, until the garlic is softened but not browned, about 3 minutes. Add the tomato paste and cook for 2 minutes.
   
2. Add the pureed tomatoes. Season with salt and pepper and bring to a boil. Reduce the heat, add the basil and dried oregano, cover and simmer, stirring occasionally, until thickened, about 45 minutes.
3. Remove the basil sprig. If the sauce is still too lumpy, mash the large tomato pieces with a potato masher. Season with salt and pepper to taste. Let cool.
4. Shells and filling:
   
   Bring a large saucepan of salted water to a boil over high heat. Add the clams and cook, stirring occasionally, until al dente. The shells should be pliable enough to be stuffed but still firm enough to finish cooking while baking. Drain and rinse the shells under cold water to stop the cooking. Drain thoroughly again.
   
5. Preheat oven to 190°C.
6. Combine the ricotta, mozzarella, Parmesan, parsley, and egg in a large bowl until smooth. Season generously with salt and pepper. Transfer the filling to a large disposable pastry bag or a large zip-lock plastic bag (or you can spoon it in).
7. Spoon 2.5 cups marinara sauce into a 9x13-inch baking dish. Snip the corner of a pastry bag and pipe the filling into the shells. Arrange the shells, open side up, in a tight layer in the baking dish. Top with the remaining marinara sauce. Cover the dish tightly with foil and bake until the sauce is bubbling and the filling is heated through, about 35 minutes.
8. Remove the foil from the pan and continue baking for another 10 minutes to allow the sauce to reduce slightly. Let cool slightly before serving. Sprinkle with grated Parmesan cheese.