1. Set a 4 to 6 quart pot filled with salted water over high heat and bring to a boil. Add the shells and cook until al dente, about 12 minutes. Gently remove the shells with a slotted spoon and transfer to a baking sheet. Drizzle 2 tablespoons of the olive oil over the shells to prevent them from sticking to one another and set aside to cool.
2. Preheat the oven to 350°F.
3. While the shells are cooling, make the stuffing. Melt the butter in a 10-inch skillet set over medium-high heat. Add the onion and cook, stirring, until translucent and soft, about 2 minutes. Add 1 tablespoon of the garlic and cook for 1 minute longer. Increase the heat to high, add the mushrooms, and cook until the mushrooms are nicely browned and the liquid has evaporated, about 4 minutes. Add 1⁄2 teaspoon of the salt, 1⁄2 teaspoon of the pepper, and the Marsala. Cook until the liquid is absorbed, about 1 minute more. Remove the pan from the heat and set aside.
4. In a medium bowl, combine the ricotta, red peppers,
herbs, mushroom mixture, and egg with the remaining 2 tablespoons olive oil, 1 tablespoon garlic, 1 teaspoon
salt, and 1⁄2 teaspoon pepper. Stir well to combine.
5. Choose the 24 nicest shells (you may have a few that have
torn or broken during cooking). Place 2 tablespoons of the
stuffing in each shell and place them, open end down, in a
9 × 13-inch casserole dish. Any extra filling may be placed in any extra shells that are available. Pour the marinara sauce evenly over the shells and top with the grated mozzarella and Parmesan. Bake until the cheese is melted and the shells are heated through and lightly browned on top, about 30 minutes. Serve hot.
Yield: 6 servings