In a large pot, sautee onion, jalepeno pepper, and garlic about 15 min. Add vegetable broth, potato, salt, chili powder, and cumin. Cook, stirring often, for 30 minutes, or until potato is tender. Process potato mixture with pumpkin and fresh cilantro in a blender until smooth (I had to do mine in two batches). Return to pot and simmer for 10 minutes. Stir in lime juice and garnish with cilantro sprig.