Preheat oven to 400°F Place 4 16-inch lengths of foil on work surface. Fold foil in half from short side. Unfold. Shape corners and edges of one half into semicircular bowl' with 1/2-inch sides. Coat insides of foil with cooking spray.
Combine sweet potato, bell pepper, green beans, and raisins in medium bowl. Add oil, and toss to coat. Season with salt and pepper, if desired.
Whisk together broth, ginger, garlic, and curry powder in small bowl.
Divide sweet potato mixture among packets; top with 1/3 cup lentils. Pour 1/4 cup broth mixture over lentils, and season with salt and pepper, if desired. Fold ther half of foil over ingredients, and crimp edges in overlapping folds until packets are sealed. Transfer packets to baking sheet. Bake 25 minutes.
Transfer to plates. Let each person open packet carefully - escaping air will be hot. Top with chutney, if using.