In a bowl, mix the ricotta with the grated aged pecorino, chopped pistachios, eggs, breadcrumbs, some salt and pepper, and the basil leaves (washed, patted dry and ripped up by hand). Carefully clean and wash the spinach, put it in a saucepan while still dripping wet and put the lid on. Cook for a few minutes stirring several times; the volume of the spinach will diminish considerably during cooking. Strain the spinach when it’s still “al dente” (the leaves mustn’t fall apart), wait 5-10 minutes for it to cool a little, then squeeze it well, forming small balls, and chop it coarsely with a knife. Now heat the oil in a heavy-bottomed frying pan and add the shallot (cleaned and finely chopped). When it has turned golden brown, add the spinach, season with salt and cook over a low heat, stirring with a wooden spoon. Turn off the heat and leave to cool down.
Lay a sheet of greaseproof paper on your work surface, tip the ricotta mixture onto it and shape it into a rectangle approximately 1.5 cm thick. Create a layer of spinach on top and then a layer of slices of fresh pecorino. Now, using the greaseproof paper to help you and beginning from one of the long sides, roll everything up; wrap the paper all around the roll and tie both ends up tightly with string. Transfer the roulade into a baking pan, cover with kitchen foil and cook in a preheated oven, at 180 °C, for 40 minutes. Take it out of the oven, leave it to cool down completely and, after removing the paper, lay your roulade “roast” on a chopping board and cut it into slices about 2 cm thick. If you like, you can serve it with a tomato sauce and a few basil leaves.
(1) “Gattò” (pronounced like the French gâteau) is the name, inherited during French dominion and revisited “Arezzo-style”, of a cake from this area that, in its shape and colour, recalls the dish described in this recipe.