Take lamb's brain, or calf's brain, put it in a saucepan with cold water, change the water from time to time for a couple of hours, until the brains are thoroughly cleansed. Then put them in another saucepan with fresh water, and with onion, salt, vinegar, and some parsley stems. As soon as the water boils, take the saucepan off, remove the brains, and put them onto a napkin. Cut them into four pieces, put these pieces onto a plate, and season with olive-oil, lemon juice, and chopped parsley. When you are ready to fry, roll in flour, dip in egg, and fry the brain over a moderate fire for seven or eight minutes in olive-oil, lard, or butter.