In a medium sauté pan, heat olive oil over medium heat. Cook the onions, stirring occasionally, until soft and caramelized, about 5-7 minutes.Stir in the curry powder and coriander,cooking for another minute to toast the spices.
Drizzle in the honey, tamarind water and lemon juice. Bring to a boil and then take off the heat and set aside to cool completely.
In a large bowl combine the lamb, apricots, peaches and rosemary sprigs. Pour the marinade over, folding to coat completely. Cover and marinate, refrigerated, for 4 hours or up to overnight.
Soak 8 wooden skewers in warm water for 10 minutes. Remove the marinating lamb mixture from the refrigerator. Thread ingredients onto the skewers alternating between lamb, peach and apricot, repeating for three combinations on each skewer.
Heat a large grill pan over medium high heat or preheat an outdoor grill. Grill kebabs for 15-20 minutes, about 3-5 minutes per side. Transfer to a platter, garnish with rosemary sprigs and serve with Basmati Rice with Pistachio Pesto.