Using a knife, cut the lamb into large chunks. Heat the oil in a large pan with two cloves of garlic, and add the meat. Brown for a few minutes until golden in colour, and pour over a glass of white wine. Leave to evaporate, cover the pan and cook for about twenty minutes.
Crush the garlic clove in a mortar with a spoonful of well-rinsed capers and a spoonful of vinegar. Combine this mixture with the chunks of lamb, and cook through. To make the sauce, grind the truffle in a mortar, adding a little extra-virgin olive oil, a few drops of lemon, salt and pepper. Remove the lamb from the oven dish and serve hot, sprinkled with the truffle sauce.