To make the filling, preheat an oven to 400°F (200°C).

Prick the 1-lb. (500-g) piece of squash several times with a fork and place it on a baking sheet.

Roast in the oven until tender when pierced with the tip of a knife, 45 to 50 minutes. Set aside to cool.

While the squash is cooking, in a small sauté pan over medium heat, warm 1 Tbs. of the olive oil. Add the shallots and sauté until translucent, 2 to 3 minutes. Remove from the heat and set aside.

In a food processor, combine the pepitas and walnuts and pulse until finely chopped. Add the shallots, egg yolk, cheese, lemon zest, nutmeg and a large pinch each of salt and pepper.

When the piece of roasted squash is cool enough to handle, scrape the flesh from the peel into the food processor with the egg yolk and cheese mixture. Process until the mixture is smooth. Transfer to a bowl, cover and refrigerate until completely cool, at least 1 hour or up to overnight.

Divide the pasta dough in half. Using a pasta machine or a floured rolling pin, roll out one of the dough halves about 1/16 inch (1.5 mm) thick. Using a knife, lightly mark the dough into 1 1/2-inch (4-cm) squares. Place 1 tsp. filling in the center of each square. Roll out the remaining dough in a rectangle of the same size and place it over the filling. Lightly press down around each mound of the filling to seal the ravioli. Using a pastry wheel or knife, cut around each mound of filling to make 1 1/2-inch (4-cm) squares. Crimp the edges to seal. (The ravioli can be made up to 2 hours in advance. Place in a single layer on a floured kitchen towel, dust the tops with flour and cover with another towel.)

When ready to serve, in a sauté pan over medium heat, warm the remaining 2 Tbs. olive oil. Add the sliced squash and cook until tender, about 3 minutes. Remove from the heat and keep warm.

In a small saucepan over medium heat, warm the butter until melted, stirring constantly. When the butter is hot, add the sage leaves and cook until crispy, 1 to 2 minutes. Using a slotted spoon, transfer the leaves to a paper towel–lined plate. Continue cooking the butter, stirring constantly, until all of the milk solids turn golden and the butter has a nutty fragrance. Be careful not to let the butter burn. Remove from the heat and keep warm.

Bring a large pot three-fourths full of salted water to a boil. Gently drop half of the ravioli into the boiling water and cover the pot. When the water returns to a boil, uncover and cook, stirring occasionally, for 3 to 5 minutes. To test for doneness, transfer a single raviolo to a cutting board and cut off a corner with a paring knife; if the pasta looks cooked through and the corner is tender, the pasta is done. Using a skimmer or slotted spoon, transfer the ravioli to a serving dish. Repeat to cook the remaining ravioli.

Drizzle the brown butter over the ravioli, then sprinkle evenly with the sage leaves and butternut squash slices. Garnish with pepitas and serve immediately, passing more cheese alongside. Serves 6.

Williams-Sonoma Test Kitchen