Ingredients
FOR THE PASTA
• 20 jumbo pasta shells
• 1 tablespoon salt, for the pasta water
FOR THE MUSHROOM FILLING
• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• 16 ounces cremini or white mushrooms, finely chopped
• 1 small yellow onion, finely diced
• 3 garlic cloves, minced
• 1 teaspoon Italian seasoning
• ½ teaspoon salt
• ¼ teaspoon ground black pepper
• 1 container (15 ounces) whole-milk ricotta cheese
• 1 cup shredded mozzarella cheese
• ½ cup grated Parmesan cheese
• 1 large egg
• 2 tablespoons chopped fresh parsley
FOR THE GARLIC CREAM SAUCE
• 3 tablespoons unsalted butter
• 4 garlic cloves, minced
• 3 tablespoons all-purpose flour
• 2 cups whole milk
• ½ cup heavy cream
• ½ teaspoon salt
• ¼ teaspoon ground black pepper
• ¼ teaspoon ground nutmeg, optional
• ½ cup grated Parmesan cheese
FOR THE TOPPING
• 1 cup shredded mozzarella cheese
• ¼ cup grated Parmesan cheese
• 1 tablespoon chopped fresh parsley, optional
Instructions
1. Preheat the oven to 375°F. Lightly grease a 9-by-13-inch baking dish with butter or nonstick cooking spray.
2. Bring a large pot of water to a boil and add 1 tablespoon of salt.
3. Add the jumbo pasta shells and cook them for about 2 minutes less than the package directions recommend. The shells should be flexible but still slightly firm.
4. Drain the shells carefully. Arrange them in a single layer on a lightly oiled baking sheet so they do not stick together.
5. Melt 2 tablespoons of butter with the olive oil in a large skillet over medium-high heat.
6. Add the chopped mushrooms and onion. Cook for 8 to 10 minutes, stirring occasionally, until the mushrooms release their moisture and the liquid evaporates.
7. Add the garlic, Italian seasoning, ½ teaspoon salt, and ¼ teaspoon black pepper.
8. Cook for 30 seconds, stirring constantly. Remove the skillet from the heat and let the mushroom mixture cool for about 10 minutes.
9. In a large bowl, combine the ricotta, 1 cup mozzarella, ½ cup Parmesan, egg, and chopped parsley.
10. Stir the cooled mushroom mixture into the cheese mixture until evenly combined.
11. To make the sauce, melt 3 tablespoons of butter in a medium saucepan over medium heat.
12. Add 4 minced garlic cloves and cook for about 30 seconds, stirring constantly.
13. Sprinkle in the flour and whisk continuously for 1 minute.
14. Slowly pour in the milk while whisking to prevent lumps.
15. Add the heavy cream, ½ teaspoon salt, ¼ teaspoon black pepper, and nutmeg, if using.
16. Cook for 4 to 6 minutes, whisking frequently, until the sauce thickens enough to coat the back of a spoon.
17. Remove the saucepan from the heat. Stir in ½ cup Parmesan cheese until melted and smooth.
18. Spread approximately one-third of the garlic cream sauce over the bottom of the prepared baking dish.
19. Fill each cooked shell with about 2 tablespoons of the mushroom and ricotta mixture.
20. Arrange the filled shells open-side up in the baking dish.
21. Spoon the remaining garlic cream sauce over and around the stuffed shells.
22. Sprinkle 1 cup mozzarella and ¼ cup Parmesan evenly over the top.
23. Cover the baking dish loosely with aluminum foil and bake for 20 minutes.
24. Remove the foil and bake for another 10 to 15 minutes, until the sauce bubbles and the cheese is melted and lightly golden.
25. Let the stuffed shells rest for 5 to 10 minutes before serving.
26. Garnish with chopped parsley, if desired, and serve warm.
Notes
• Cook the pasta shells about 2 minutes less than the package recommends. Overcooked shells can tear while being filled.
• Cook the mushrooms until nearly all their released liquid has evaporated. Excess moisture can make the filling watery.
• Allow the mushroom mixture to cool before adding it to the ricotta filling so it does not begin cooking the egg.
• White button mushrooms, cremini mushrooms, or a combination of mushrooms may be used.
• Add 1 cup of cooked, finely chopped spinach to the filling, if desired. Squeeze out as much moisture as possible first.
• Cottage cheese may replace the ricotta. Blend it briefly for a smoother filling.
• Approximately 3 cups of prepared Alfredo sauce may replace the homemade garlic cream sauce.
• To prepare ahead, assemble the stuffed shells, cover the dish, and refrigerate for up to 24 hours.
• A refrigerated casserole may need approximately 10 additional minutes of covered baking time.
• Store leftovers in an airtight container in the refrigerator for up to 4 days.
• Reheat covered in a 350°F oven or microwave individual portions with a small spoonful of milk or cream sauce.
• To freeze, assemble the stuffed shells in a freezer-safe dish and cover tightly. Freeze for up to 3 months.
• Thaw overnight in the refrigerator before baking.