Cut bell peppers in half lengthwise; discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet, and flatten peppers with hand. Broil 15 minutes or until skin looks blackened. Place in a zip-top plastic bag, and seal. Let stand 10 minutes. Peel and coarsely chop.
Heat 2 teaspoons olive oil in a large saucepan over medium-high heat. Add onion, shallots, and garlic; cook 3 minutes, stirring occasionally. Add celery and carrot; cook 2 minutes. Add bell peppers, tomato paste, and next 6 ingredients (through beef broth), and bring to a boil. Cover, reduce heat, and simmer 15 minutes. Remove pan from heat; let stand 5 minutes. Place half of bell pepper mixture in a blender; process until smooth. Pour into a large bowl. Repeat procedure with remaining bell pepper mixture.
Ladle soup into individual bowls; top with sour cream and chives.