1. Bring a medium pot of salted water to a boil. Add the potatoes and cauliflower and cook until just tender, about 7 minutes. Drain.
2. Using a boning knife, trim off excess fat and scrape the lamb off the bones. Cut the meat into 3-by-1-by-1/4 -inch strips. Season the lamb with salt and pepper. Heat 1 teaspoon of the oil in a large, straight-sided, nonreactive skillet. Add half of the lamb in a single layer and cook over moderately high heat, turning once, until browned and crusty, about 2 minutes. Transfer to a platter. Repeat with the remaining lamb and 1 more teaspoon oil.
3. Heat 2 teaspoons of the oil in the skillet. Add the onions, jalapeños and garlic and sauté over moderately high heat until just softened, about 3 minutes. Add the potatoes and cauliflower and sauté until lightly browned, about 2 minutes. Add the vegetables to the lamb.
4. Heat the remaining 1 teaspoon oil in the skillet. Add the curry powder and cook over moderately high heat, stirring, until fragrant, about 30 seconds. Pour in the chicken stock, scraping the bottom of the pan to loosen any browned bits, and cook until reduced by two-thirds, about 3 minutes. Stir in the coconut milk, heavy cream, currants and honey and simmer until slightly reduced and thickened, about 3 minutes.
5. Return the lamb, potatoes, cauliflower and any accumulated juices to the sauce and simmer until heated through. Season with salt and pepper.
Make Ahead: The curry can be made up to 1 day ahead. Rewarm over low heat. Stir in the cilantro and serve.
Serve With: Basmati rice or nan, Indian flat bread similar to pita; it is available at some supermarkets.
Wine Recommendation: This spicy-sweet hearty dish would overwhelm reds usually served with lamb. Go for a soft and fruity red that stays in the background: an Australian Shiraz, such as the 1993 Mitchelton or the 1993 Wyndham Estate Bin 555.