Season lamb with 1 tablespoon (15 mL) curry powder. Heat 1 tablespoon (15 mL) oil in large nonstick skillet over medium-high heat and cook lamb, stirring occasionally, until lamb is browned and cooked to desired doneness, about 2 minutes; remove and set aside.
Heat remaining 2 tablespoons (30 mL) oil in same skillet and cook potatoes, onion, remaining 1 tablespoon (15 mL) curry powder and cardamom, stirring frequently, until potatoes are browned, about 8 minutes. Stir in 1 cup (250 mL) water and cook covered, stirring occasionally, until potatoes are tender, about 4 minutes. Stir in tomato sauce, half and half cream, peas and Knorr® Homestyle Stock Vegetable and cook covered, until sauce thickens slightly, about 8 minutes.
Stir in lamb. Serve, if desired, with warm naan and garnish, if desired, with chopped fresh cilantro.