Pour boiling water over the spinach, then leave to cool a little before squeezing out any excess liquid. Chop the spinach finely. Drain and squeeze out any excess water again. Put the spinach in a mixing bowl with the ricotta, egg yolks, breadcrumbs, flour, a grating of nutmeg, a pinch of salt and the cheese. Mix well.

Scoop up 24 equal-sized lumps of the mixture, using an ice cream scoop if you have one, and shape each one into a log by rolling it between your hands. Lay each log on a baking sheet, then chill for 30 mins, or until needed.

Bring a large pan of salted water to the boil. Lower the gnudi into the water, turn down to a simmer and cook for 3-4 mins (do this in batches if you need to). Meanwhile, heat the butter in a large frying pan, add the sage and fry until crisp. Drain the gnudi well, then tip into the pan with the sage, along with a good grating of cheese. Swirl everything together, doing it in batches if it’s easier. Arrange four gnudi on each serving plate, pour over more of the sauce and scatter with more grated cheese.