In a medium bowl, combine the pumpkin puree, ricotta (or mascarpone), grated Parmesan cheese, ground nutmeg, salt, and pepper. Mix thoroughly until the filling is smooth and creamy.

On a clean, floured surface, mound the all-purpose flour and create a well in the center. Crack in the eggs and sprinkle some salt. Gradually mix the flour into the eggs with your fingers until a cohesive dough forms.

Knead for about 8-10 minutes until the pasta dough is smooth and elastic. Cover it with plastic wrap to rest for at least 30 minutes.

Divide the dough into quarters. Using a pasta machine or rolling pin, roll each piece thinly into sheets about 1/16 inch thick.

Lay one sheet of rolled dough flat, place teaspoons of filling approximately 2 inches apart, brush water around edges, and lay another sheet on top before sealing.

Bring a pot of salted water to a boil and cook ravioli for 3-4 minutes until they float. Use a slotted spoon to transfer to a plate.

In a skillet, melt the unsalted butter and add fresh sage. Cook until the butter turns golden brown (5-7 minutes).

Add the cooked ravioli into the skillet with the brown butter sauce, toss to coat, and season with salt and pepper before serving.