Remove lamb from refrigeration up to two hours prior to grilling and rest on the counter, elevating to near room temperature. 30 minutes before laying lamb to flame, preheat grill to medium-high heat. Meanwhile, and brush entirety of the lamb with butter, then generously season with the dry rub.
Position lamb over direct heat and with the grill lid open cook 3-4 minutes per side until nicely charred. Reposition the lamb away from the direct heat source (charcoal, gas and/or wood), basting intermittently with butter, until internal temperature reads 125-130F. Remove lamb from the grill, transfer to a cutting board, finish with a dusting of your favorite fleur de sel (I used birchwood-smoked fleur de sel) and crushed pink peppercorn. Rest for 5-10 minutes before serving.
Dress with fresh herbs and plate over a bed of charred greens. Pair alongside an ice cold ale or IPA.