Wash the tongue and place it in a large, heavy-based saucepan.
Cover with water and bring to the boil. Remove the scum.
Add the onion and remaining ingredients, reduce the heat and simmer gently for about four hours, until the tongue feels tender when pierced with a pointed knife.
Add more water if necessary to keep the meat covered.
Remove the tongue and peel off the skin while it is hot.
Remove any bones at the throat.
Return the tongue to the broth.
Slice thinly just before serving.
Serve hot or cold with hot or cold sauce.
To prepare the sauce, put the chopped parsley and mint into a bowl.
Blend the anchovies, capers, pickled cucumbers, breadcrumbs and hard-boiled egg yolks in a food processor.
Add to the chopped herbs and mix in the garlic, vinegar, sugar, salt and freshly ground black pepper, to taste.
Beat in the olive oil to make a fluid sauce.
Tongue cooks successfully in a pressure cooker.
It will take approximately one hour to cook.