1. In a large pan, warm oil over medium heat. Cook onion, carrot and celery, stirring often, until softened, about 8 minutes. Add garlic; sauté for 1 to 2 minutes longer. Add curry powder; sauté for 2 minutes longer.
2. Stir in broth, lentils, 2 tsp. salt and 1/2 tsp. pepper. Bring to a boil over high heat, cover pot, reduce heat to medium-low and simmer until lentils are very soft, about 40 minutes. Remove from heat and let cool slightly. Working in batches, puree half of soup in a blender until nearly smooth. Return pureed soup to pan. Stir in coconut milk and reheat gently over medium-low heat, stirring occasionally; do not boil. Season with salt and pepper. Ladle into bowls and sprinkle with chopped cilantro just before serving, if desired.