Boil the tongue in plenty of boiling water for about 20–30 minutes, depending on the tenderness of the veal tongue used.
Drain and set it aside.
In a skillet, add the sliced onions and a drizzle of extra virgin olive oil.
Cook over low heat until the onions have softened.
Cut the boiled tongue into bite-sized pieces or slices, then add it to the skillet along with salt and chili pepper to taste. Continue cooking until the onions have broken down completely into an almost creamy consistency. Add a little water as needed during cooking.
Serve the Genoese-style veal tongue warm, ideally accompanied by toasted bread crostini.