Method

• 1.
  If using raw cotechino, soak in cold water for 4 hours. Drain, prick skin and wrap in foil. Bring a pan of water to the boil, then reduce heat to medium-low, add sausage and cook for 2 1/2 hours (or 30-40 minutes for pre-cooked) or until tender and juices run clear when pierced. Remove from heat and stand in water for 15 minutes.
• 2.
  Meanwhile, place potato in a saucepan of cold, salted water. Bring to the boil, then simmer over medium-high heat for 15-20 minutes until tender.
• 3.
  Place olive oil in a saucepan over medium-low heat. Cook garlic, stirring, for 3-4 minutes until soft and fragrant.

• 4.
  Drain potatoes, then return to pan and mash until smooth. Beat garlic oil, truffle oil and milk into the potato with a wooden spoon, then season.
• 5.
  Drain cotechino, slice thickly, then serve on mash with the rocket.