Pour flour into a pile on a work surface and hollow out the center.
Whisk eggs into the hollow and gradually incorporate flour to form a paste.
Knead dough until smooth, then let it rest for 30 minutes.
Sauté spinach, chop it, and mix with ricotta, Parmigiano, nutmeg, salt, and pepper.
Roll out dough using a pasta machine, cut in half, and flatten into sheets.
Place ricotta stuffing on one sheet, cover with the other, press down, and cut into squares.
Boil ravioli for 2-3 minutes, then toss in a pan with melted butter and sage leaves.
Serve topped with sauce and sage leaves.
After making the dumplings, arrange them on a baking sheet or platter dusted with flour. Make sure the ravioli aren’t touching each other or they’ll stick together. Freeze them until solid, at which point you can transfer the pasta into a freezer bag.
Cook frozen ravioli directly from the freezer, don’t thaw them in advance. They’ll take slightly longer, maybe 30-60 seconds more than normal.