If you bought the rack frozen, let it thaw in the fridge overnight or at room temperature for several hours.

Preheat oven to 425 F, with the oven rack in the centre position.

On a big plate (preferably something like this, with a lot of surface space but a bit of edge) combine bread crumbs, garlic, rosemary, 1 teaspoon salt, 1/4 teaspoon pepper and lemon zest. Toss in 2 tablespoons olive oil to moisten mixture. Set aside.

Season rack with salt and pepper. Heat 2 tablespoons olive oil (this is where I used duck fat instead) in a large skillet over medium-high heat. Sear rack of lamb for 1 to 2 minutes on all sides. Set aside for a few minutes. Brush rack of lamb with mustard. Roll in the bread crumb mixture until evenly coated. Cover the ends of the bones with foil to prevent charring.

Arrange the rack bone side down on a baking sheet lined with foil and roast for 18-20 minutes. Take it out of the oven and tent it with foil for about five minutes to let all the juices absorb back in. Carve.

For the mashed potatoes, I used two medium potatoes, a couple tablespoons of butter, salt, pepper, dried rosemary and chives, a pinch of nutmeg and 3-4 strips of bacon, cooked and crumbled.