Sula (sometimes written sule) is the traditional barbecue of Rajasthan, the northwest province that includes the Thar (Indian) Desert. It's unique in several ways. First, the meat: traditionally venison, wild boar or rabbit is used. (Rajasthan is famous for its wild game and its hunters.) Since deer is an endangered species in India, these days most sula is made from lamb or baby goat.
Second, the cut of the meat: unlike the chunks or ground meat used for grilling elsewhere in India, sula is made from thin broad slices threaded onto skewers.
Third, the heat source: while sula can, like most Indian barbecue, be cooked in a tandoor (an urn-shaped clay oven), in Rajasthan it's customarily done on a hibachi-like grill.
And finally, the seasoning: it's a piquant mixture of yogurt, ginger, garlic and lemon juice with a touch of heavy cream for richness and a blast of cayenne pepper for bite.