Preheat oven to 450 degrees. Pulse pancetta, garlic, cheese, breadcrumbs, mint, lemon juice, 1 teaspoon salt, and some pepper in a food processor until combined. Add artichokes. Pulse a few times, keeping mixture chunky.
Lay lamb flat on a work surface, skin side down. Season with salt. Spread artichoke mixture over top, leaving a 1/2-inch border. Tightly roll lamb, and tie with kitchen twine at 2-inch intervals to hold.
Rub lamb with oil, and season generously with salt and pepper. Transfer to a roasting pan fitted with a roasting rack, and add water to pan. Roast for 30 minutes. Reduce oven temperature to 350 degrees. Continue to roast until an instant-read thermometer reaches 130 degrees to 135 degrees (for medium-rare), 1 hour to 1 hour 15 minutes. Let rest for 20 to 30 minutes before carving. Serve with mint sauce.
I used a 5+ pound boneless leg of lamb; pepper bacon instead of pancetta and two bags of frozen artichoke hearts and removed some of the sometimes tougher outer leaves. It took 1:45 to cook and got nice and crispy on the outside. I, unfortunately, had to let it sit longer than I would have liked before eating, so it cooked a bit more than it should have. It was still very tasty. Be sure to use LOTS of mint in the sauce - 'a bunch of mint' means different things to different people!