To prepare the sheet of pasta: put the flour on a pastry board or your kitchen work surface, heap it up a create a “well” in the centre, break the 4 eggs into it and add a pinch of salt. Start mixing slowly with a fork, and then use your hands until the dough forms a smooth, compact ball. Roll out the dough into a thin sheet (roughly 2 mm thick) with a rolling pin, use a few handfuls of flour to make sure that it doesn't stick to the surface and try to give it an oval shape. If you don’t have much room, divide the dough in half and roll each piece out separately. Leave the pasta to dry on a lightly floured cloth. Then cut it into rectangles of about 12 x 24 cm (naturally this is only an approximate size!) and lay them on a chopping board, even overlapping if you wish: sprinkle a little flour between them so they don’t stick together.

Put a large saucepan full of water on the stove: when it comes to the boil, add a good pinch of coarse salt and a tablespoon of olive oil. Fill a large bowl, or a casserole dish, with cold water and place it as close as possible to the stove. Take one piece of lasagna at a time and put it into the boiling water vertically: drop it in slowly and then continue with the others, but without overfilling the saucepan (if necessary cook them in two or three batches). They will cook very quickly, after a minute or two use a perforated spoon to remove them from the pan. Put them straight into the cold water in the bowl and spread them out with your hands, then lay them out one beside the other on a cotton cloth.

To prepare the filling: clean and coarsely chop the onions, then put them in a bowl with the sieved ricotta, salt, pepper and grated nutmeg. Stir everything together thoroughly, add the milk a little at a time, and continue stirring until you obtain a smooth mixture. Pour a few spoonfuls of Peperotta into the bottom of the baking pan (previously greased with olive oil), distribute it evenly and cover it with the first layer of lasagna, arranging the sheets one beside the other. Sprinkle with some grated pecorino cheese, pour an abundant dose of the ricotta mixture on top, spread it out well and cover with a second layer of lasagna. Continue with another layer of Peperotta, a layer of pasta sprinkled with pecorino and a layer of the ricotta mixture, until you finish the ingredients. Finish off with Peperotta: sprinkle the surface with the remaining pecorino and garnish, as you prefer, with a few pieces of fresh bell pepper. Cook the lasagna in a preheated oven, at 180 °C, for approximately 40 minutes: it will be ready when a nice golden crust has formed on the top. Before serving, leave it to cool down for a few minutes.