Heat 1 tablespoon oil in large pan; cook chilies, nuts and onions, stirring, until onions are browned lightly. Cool. Blend or process onion mixture with half the blended coconut milk powder and water. Heat remaining oil in same pan; cook garlic, ginger and spices, stirring, until fragrant. Add pureed onion mixture, remaining coconut milk mixture and undrained crushed tomatoes; simmer, covered, for 1 hour. Remove the cover; simmer about 1 hour or until lamb is tender. Stir lamb into spice mixture; add yogurt gradually, in batches, stirring well between additions.