In a large mixing bowl, combine the pumpkin puree, ricotta cheese, egg, salt, and nutmeg. Mix until smooth and well combined.

Gradually add the flour, one cup at a time, mixing until a soft dough forms. You may need more or less flour depending on the moisture of the pumpkin.

Turn the dough out onto a floured surface and knead gently for about 1 minute until the dough is smooth. Be careful not to overwork it.

Divide the dough into 4 equal portions. Roll each portion into a long rope about 1/2 inch thick. Cut the rope into 1-inch pieces to form the gnocchi.

Use a fork to gently press down on each piece to create ridges, which will help hold the sauce.

Bring a large pot of salted water to a boil. Carefully drop the gnocchi into the boiling water in batches. Cook until they float to the surface, about 2-3 minutes. Remove with a slotted spoon and set aside.

In a large skillet, heat the olive oil over medium heat. Add the cooked gnocchi and sauté for 2-3 minutes until lightly golden.

Serve hot, garnished with grated Parmesan cheese and fresh sage leaves if desired.