Ricotta Spinach Gnudi (Naked Ricotta Dumplings)

Blanch 180 g spinach for only 30 seconds, cool it in cold water, and squeeze it very firmly in a cloth. Continue until almost no drops come out, then chop it finely. Combine the spinach with 350 g ricotta, 60 g Parmigiano Reggiano, 2 egg yolks, and salt, pressing gently with a spatula until the green pieces are evenly distributed. Start with only half of the 90 g all-purpose flour. The mixture should hold together while remaining slightly tacky. If it is still loose, add more flour 1 tablespoon at a time rather than tipping in the remainder automatically. Excess flour and heavy handling both make the dumplings dense. Chill the mixture for 20 minutes. Lightly dust your hands and a tray with the remaining flour, then roll small ovals without compacting them. Keep a wide pot of salted water at a gentle boil, since violent bubbling can knock the soft gnudi against one another. Add them in batches. Once a dumpling floats, cook it for 1 minute more and lift it out carefully with a slotted spoon. For the finish, melt 50 g unsalted butter with 8 sage leaves over medium-low heat until the butter turns light brown and smells nutty. Add the drained gnudi and roll them very gently to coat their surfaces without breaking them. Serve immediately while the brown butter is fluid and the centers remain tender.