1. To make Balsamic Reduction: Bring vinegar and agave nectar to a boil in small saucepan. Reduce heat to medium, and simmer 15 minutes, or until thickened. Cool.

2. To make Soup: Heat oil in large pot over medium heat. Add red onion, sweet potato, Yukon gold potato, and shallot, and cook 5 to 7 minutes. Add cumin, red pepper flakes, and garlic. Sauté 3 to 5 minutes. Add broth and bell peppers; bring to a simmer. Cook 30 minutes, or until bell peppers and potatoes are softened. Blend Soup in batches until smooth. Season with salt and pepper, if desired. Drizzle each serving with Balsamic Reduction.