UNSTUFFED SHELLS WITH BUTTERNUT SQUASH AND LEEKS

Makes: 4 to 6 servings

Notes: You can substitute large or medium shells, ziti, farfalle, campanelle or orecchiette for the jumbo shells. The skillet will be very full when you add the shells in Step 3 (stir gently to start), but will become more manageable as the liquid evaporates and the shells become more malleable. You will need a 12-inch oven-safe nonstick skillet.

8 ounces (1 cup) whole-milk ricotta cheese 2 ounces Parmesan cheese, grated (1 cup) 1 teaspoon grated lemon zest

Salt and pepper

1 tablespoon extra-virgin olive oil

1 ½ pounds butternut squash, peeled, seeded and cut into ½-inch pieces (5 cups) 1 pound leeks, white and light green parts only, halved lengthwise, sliced thin and washed thoroughly

2 garlic cloves, minced

Pinch cayenne pepper

¼ cup dry white wine

4 cups water

1 cup heavy cream

12 ounces jumbo pasta shells

2 tablespoons chopped fresh basil

1. Adjust oven rack to middle position and heat oven to 375 degrees. Combine ricotta, ½ cup Parmesan, lemon zest, ¼ teaspoon salt and ¼ teaspoon pepper in a bowl; cover and refrigerate until needed.

2. Heat oil in a 12-inch oven-safe nonstick skillet over medium heat until shimmering. Add squash, leeks and ½ teaspoon salt, and cook until leeks are softened, about 5 minutes. Stir in garlic and cayenne and cook until fragrant, about 30 seconds. Add wine and cook until almost completely evaporated, about 1 minute.

3. Stir in water and cream, then add pasta. Increase heat to medium-high and cook at a vigorous simmer, stirring gently and often, until pasta is tender and liquid has thickened, about 15 minutes.

4. Season with salt and pepper to taste. Sprinkle remaining ½ cup Parmesan over top, then dollop evenly with ricotta mixture. Transfer skillet to oven and bake until Parmesan is melted and spotty brown, about 5 minutes. Remove skillet from oven. (Skillet handle will be hot.) Let cool for 10 minutes, then sprinkle with basil and serve.