Mound flour and salt, create a well, add eggs and oil, and mix into a shaggy dough. Knead for 8 to 10 minutes until smooth, then wrap and rest for 30 minutes.

Wilt spinach in a dry pan over medium heat for 2 to 3 minutes, squeeze dry, chop finely, and mix with ricotta, Parmesan, nutmeg, salt, and pepper.

Divide dough, roll through a pasta machine to the thinnest setting, or roll by hand until almost translucent. Dust with flour to prevent sticking.

Place small mounds of filling on one sheet, brush water around them, top with a second sheet, seal without air pockets, and cut into individual ravioli.

Boil ravioli in salted water for 3 to 4 minutes until they float. Remove with a slotted spoon and drain gently.

Melt butter in a skillet, add sage, and cook until golden and nutty, about 3 to 4 minutes. Toss ravioli in the butter and serve immediately with extra Parmesan.