Mound the flour on a clean work surface and make a well in the center. Crack in the eggs, then add the salt and olive oil. Use a fork to slowly whisk the eggs while pulling in flour from the inside edges. Keep going until the mixture becomes too thick to stir with a fork. Then use your hands to bring the dough together and knead it for 8 to 10 minutes, until smooth and elastic. After that, wrap it and let it rest at room temperature for 30 minutes.

While the dough rests, stir together the pumpkin puree, ricotta, Parmesan, nutmeg, salt, and pepper in a medium bowl until smooth and well blended. Transfer it to a piping bag or a zip-top bag with the corner snipped off.

Divide the rested dough into 4 pieces and keep the pieces covered. Roll one piece at a time until very thin, about 1/16 inch thick. Pipe small mounds of filling across half of the sheet, about 2 inches apart. Fold the other half over and press firmly around each mound to seal.

Use a sharp knife or pastry wheel to cut between the mounds and form individual ravioli squares. Place them in a single layer on a lightly floured baking sheet.

Bring a large pot of salted water to a boil and cook the ravioli in batches for 3 to 4 minutes, or until they float and feel tender. Meanwhile, melt the butter in a skillet over medium heat until golden with brown flecks. Add the sage leaves and cook until crisp. Add the cooked ravioli to the skillet and toss gently. Stir in the Parmesan, salt, and pepper, then serve with extra Parmesan and black pepper on top.