In keeping with Senegalese tradition, Sean Brock likes to make this dish with all parts of the lamb. But here he calls for just the leg, which is easier to skewer and grills up beautifully. Slideshow: More Recipes for Leg of Lamb
In a medium bowl, combine the white vinegar with the Dijon mustard and agave nectar. Stir in the onion slices and season with salt and white pepper.
Light a grill or preheat a grill pan and oil the grates. In a large bowl, toss the lamb with the 1 tablespoon of peanut oil and season generously with salt and black pepper. Thread the lamb pieces onto 8 skewers. Grill the lamb over moderate heat, turning occasionally, until it is charred in spots, 6 to 7 minutes for medium meat. Transfer the lamb skewers to a platter and serve with the mustard onions.
The mustard onions can be refrigerated in an airtight container for up to 2 days.
Nutty amber ales complement the smokiness of grilled meats.