2 pounds boneless lamb shoulder, cut into 6 pieces
½ cup soy sauce
½ cup mirin
1 cup sake
2 cups water or stock
⅓ cup sugar
1 ¾ ounces kombu
5 pieces dried shiitake mushrooms
1 carrot, peeled and cut into pieces
1 daikon, peeled and cut into pieces
Preheat the oven to 250ºF. Lightly sear the lamb, remove from heat and pat dry with absorbent paper.
Mix soy sauce, mirin, sake, water or stock, and sugar together and add the kombu and dried shiitake mushrooms. Set aside.
Heat the oil in a large flameproof casserole dish, large enough to hold the lamb, over medium-high heat. Sear the lamb until golden brown. Remove from heat and drain the fat. Return the lamb to the heat. Place the carrot and daikon around the meat. Add the soy sauce mixture to cover the lamb by an inch and bring to a simmer over high heat.
Cover and transfer to the oven. Braise gently until the lamb is tender (at least 5 hours) then turn off the heat and chill.
To reheat, bring lamb back to room temperature and heat to a core temperature of 150ºF. Serve with a bowl of steamed rice and miso soup.