Steam or cook in a little hot water, the spinach (previously thoroughly washed), drain, chop it up and finely sieve. Flavor the puree with 2 Tbsp of butter, transfer to a bowl, leave to cool, and add to it the sieved Ricotta, egg yolks and 3 oz of Parmesan. Season with salt and pepper. Prepare some dough with 1,1 lb of sieved flour, 5 eggs, a tablespoon of oil, and a pinch of salt. Knead the dough, leave it to rest, and roll out two large sheets. Put one of the two sheets well stretched-out on a lightly floured surface and line up on top, at a regular distance, some fairly small dollops of filling. Cover with the second sheet and join the two sheets by pressing the empty spaces with the tips of the fingers. With a toothed pasta-cutter, cut out some squares of about 1,5 inches per side. Line these up far apart on a tray covered with a lightly floured napkin. Cook the ravioli in abundant, lightly salted boiling water, drain as soon as they float to the surface, arrange on a heated plate (if possible oval), and dress with the remaining butter, softened and scattered in small pieces, the boiling liquid cream, and the remaining Parmesan. Serve immediately.