Scrub the tongue under cold water, then place in a large saucepan and cover with water. Bring to the boil, skimming off the scum that rises to the surface
Once the water is boiling, add your onions, carrots, garlic, thyme and peppercorns.
Continue to boil until tender. This takes about 3 hours for ox, pig and veal tongue, or 1–1.5 hours for lamb and smaller tongues.
Once cooked, it will have turned white and the top of the tongue will start to blister.
Remove the tongue from the liquor, and when cool enough to handle peel off and discard the rubbery skin.
Make sure you do this whilst still warm as it’s near impossible to do cold. Remove the rough, bony end of the tongue and discard.
At this stage, the tongue can be pressed with a little of the cooking liquor and some gelatine, left in the fridge overnight, then thinly sliced for sandwiches. Or, due to its rich, fatty texture, dice it up and fry in butter until crispy for a luxurious melt-in-the-mouth finish.