1/2 cup plus 2 tablespoons extra-virgin olive oil, plus more for oiling the grill
4 tablespoons herbes de Provence
Twelve 1/2-inch-thick lamb rib chops (see Cook's Note)
Kosher salt and freshly ground black pepper
2 lemons, halved crosswise
2 bunches (about 8 cups) watercress
Ask your butcher to separate the rack of lamb ribs for you, but make sure you tell him or her to keep the fat on (i.e., do not French the bones)--you want the fat for grilling. Not only will it prevent the meat from drying out, but it will also give a great amount of flavor to your finished dish.