Simmer the cotechino, still in its pouch, in enough water to cover for about 20-30 minutes to reheat it.

In the meanwhile, prepare the lentils: simmer the lentils in water with a sprig of sage or rosemary or another aromatic herb and a clove of garlic until tender.

In a separate pot, make a simple soffritto of onion (and if you like, some finely minced prosciutto or pancetta) in olive oil and butter until soft and translucent. Strain and add your just cooked lentils to the soffritto, allowing them to simmer together for a few minutes, then add a ladleful or two of rich broth or the lentil cooking liquid or, best of all, the juice from the cotechino (see next paragraph). Simmer long enough for the flavors to meld and the lentils to become entirely tender. Do not overcook the lentils, however, or they will become rather stodgy.

When the lentils are just about done, carefully remove the cotechino from its pouch by cutting open up one side and allowing its contents—the cotechino itself and a fair amount of fatty juice—into a deep serving dish, preferably oval in shape to accommodate the cotechino comfortably. That juice has wonderful flavor: I like to add a ladleful or so to the lentils and let them absorb that flavor.

To serve, remove the cotechino to a cutting board and slice it thickly. Then lay out of 'bed' of the lentils in a large serving platter, then the cotechino slices in a pleasant arrangement on top of the lentils. You can, if you like, add a bit more of the juice on top of the lentils for even more lovely flavor and unctuousness.