First you need to think about the preparation of the broth: although its use is not essential, since we can use hot salted water or the carasau bread can be softened directly by the tomato sauce, certainly the flavor of our dish will benefit from it. The most suitable broth, if you want to follow tradition and add a strong flavor to the dish, is sheep broth; however, any meat broth or, should you prefer it, a vegetable broth can be fine.
It is then necessary to prepare a very simple tomato and basil sauce. Take an onion, peel it, chop it and brown it over a gentle flame in a saucepan together with a few tablespoons of extra virgin olive oil. Then add the tomato puree (or pulp), the necessary salt and cook over medium heat for about 15 minutes. Season the sauce with a few basil leaves.
You have now reached the crucial stage of preparing pane fratau. The pane carasau, the main ingredient of our dish, must be cut into large pieces; alternatively, you can use the one already cut into quarters found in the market. Arrange several large serving dishes in front of you, depending on the number of diners. Using a skimmer, dip the bread very quickly into the hot broth so that it softens but does not become completely soggy, thus retaining its texture. Lay three pieces of bread on each plate and cover with a generous layer of sauce and plenty of grated Sardinian pecorino cheese (modern variants also suggest using Grana Padano cheese). Repeat for two or three more layers-there is no real rule about this.
You can now deal with the preparation of the poached eggs. Pour water and vinegar (in a ratio of 1l / 100 ml) into a fairly high, large saucepan and bring it to a gentle boil; if you prefer, you can use the same stock used previously for cooking, to which you will need to add the appropriate amount of vinegar. Peel one egg at a time into a small bowl, taking care not to break the yolk, and, with a whisk, stir the water so quickly that it forms a vortex, inside which you will let the egg slide. Egg that will begin to rotate on itself, until the yolk is completely enveloped by the albumen. It will take about three minutes for the cooking to be complete. When done, gently drain with a skimmer, remove any fringing egg white and dry the egg on a sheet of paper towels. Finally, gently lay a poached egg in the center of each plate and your pane fratau will be ready to serve at the table.
If you want to achieve different flavors, while departing from the traditional recipe, you can use herbs such as chicory, rosemary, thyme or oregano to flavor the dish, or, if you prefer, you can top it off with a grind of fresh pepper and a drizzle of extra virgin olive oil.
Enjoy your meal!