-
1
In a large bowl, stir together lemon zest, 2 TBSP of the salt, the red pepper flakes, 1/2 tsp of the black pepper, the chopped rosemary, thyme, garlic, 1/4 cup of the olive oil and the mustard. Coat the lamb on both sides with the mixture (I put in Ziploc bag). Cover and refrigerate for 5 to 6 hours or overnight.
-
2
Pepare a medium-hot fire in a grill or pre-heat gas grill.
-
3
Place the lamb on the center of the grill rack, close the lid and grill for 10 minutes. Turn the lamb over close the lid and cook until an instant-read thermometer inserted into the center of the lamb registers 130 to 135 for medium-rare to medium, 10 to 15 minutes more.
-
4
Transfer the lamb to a carving board, cover loosely with aluminum foil and let rest for 10 minutes before carving.
-
5
Meanwhile, in a small sauce pan over medium-high heat, add the butter and the shallots and cook until the shallots are tender, 2 to 3 minutes. Add the vinegar and cook, stirring until it is nearly evaporated, 1 to 2 minutes more. Add the stock, bring to a boil and cook, stirring until the liquid is reduced by half, 3 to 4 minutes more. Transfer the sauce to a warmed sauceboat. (Note: Mine took longer than the times listed).
-
6
Carve the lamb into thin slices and transfer to a warmed platter. Pass the sauce alongside.
