Wash the spinach thoroughly and, without shaking off the water, cook it in a saucepan over a moderate heat for a few minutes, with a pinch of salt. Spinach gives off enough water for it to be cooked in (if you cook it without the lid on, it will remain greener). Strain it, squeeze the water out (with your hands) and, on a wooden chopping board, chop it with a knife. Now toss the chopped spinach in a frying pan for a few minutes, with 2 or 3 spoonfuls of olive oil (already heated) and 2 cloves of garlic. When it has cooled down, put it in a large bowl and mix it with the ricotta, 100 g of flour, 80 g of grated pecorino, and some salt and pepper. Using your hands and a spoon, form the mixture into oval shapes (like gnocchi) about 3 cm long. Coat them in the remaining flour and lay them on a tea towel (sprinkled with flour) to rest, for about an hour.
Fill a large saucepan with water, add a little salt and bring it to the boil.
In the meanwhile, heat the butter in a large, heavy-bottomed frying pan. As soon as it has melted and begins to bubble, add the sage leaves, which you have previously washed and dried (you can either leave them whole or cut them in strips), and let them cook gently. Cook the gnudi in the boiling water; as soon as they float to the surface, strain them with a slotted spoon and delicately toss them in the frying pan with the butter and sage.
Serve your gnudi nice and hot, with plenty of grated pecorino cheese.
The name of this sort of gnocchi varies greatly throughout Tuscany: besides “gnudi” – which comes from the old Tuscan term “ignudi” (= nude) – they’re also known as “strozzapreti” (= priest stranglers).