Barbacoa-spiced slow-roasted leg of lamb

Fat side up, score the leg about every half inch, a quarter inch deep, in both directions; then stab it a couple of inches deep all over on both sides, avoiding the bone.

Mix kosher salt, black pepper, chili powder, ancho chili, ground chipotle, Mexican oregano, cinnamon and garlic powder with the juice of the orange, lemon and limes into a paste with a whisk.

Turn the lamb in the rub with a fork until completely coated.

Marinate uncovered in the fridge at least 24 hours, better two days (48 hours here), flipping halfway or several times.

Scatter the sliced onion under the rack in a roasting pan.

Toss carrot chunks and halved Yukon golds with olive oil, minced garlic and kosher salt; arrange them evenly around the outside of the pan.

Set the lamb fat side up on the rack and space the vegetables so they cook through.

Whisk a couple of cups of chicken broth in the marinating bowl and pour it all into the bottom of the pan.

Put the pan in the center of a 475 degree oven and turn it down to 300 as soon as the door closes.

Roast at 300 about two and a half to three hours, to 135 in the thickest part.

Wrap loosely in foil and rest at least 30 minutes.

Move the vegetables to a platter; if not done, return them to the oven at about 400 while the meat rests.

Pour the pan drippings into a measuring cup, let the fat rise and spoon it off.

Slice the lamb thin on a cutting board, angling the knife across the grain, which runs parallel to the bone; serve with the pan juices spooned over.

Variation: warm tortillas, top with roasted potato and cubed lamb, pan juices, finely diced white onion rinsed in cold water and mixed with fresh mint and cilantro, and a squeeze of Mexican lime.