This recipe is prepared in a food processor or blender. If your food processor bowl is not large enough to make this recipe in one batch, split the ingredients into two batches and combine in a large soup tureen after pureeing. Chill before serving.
To prepare the gazpacho: Place the tomatoes, cucumbers, shallot, celery, carrots, garlic, herbs, Tabasco sauce, and lemon juice in a blender or food processor and puree. Add enough chicken stock and tomato juice to aid in pureeing the mixture. If you are using a food processor, process with the metal blade for about 30 seconds. The consistancy of the soup will be somewhat chunky, containing small pieces of the different colored vegetables. Don't puree to a smooth texture.
Add more chicken stock and/or tomato juice, depending on how thick or thin you prefer your soup. The amount of stock and juice you use will also depend on the amount of liquid contained in the vegetables.
Add salt and pepper to taste. Stir in the red and yellow bell peppers. Chill for at least 1 hour before serving.
To prepare the pesto: Place the basil, garlic, and parmesan in a food processor fitted with a metal blade. Puree while slowly adding about 1 cup of the olive oil. When smooth, add the pine nuts, season with salt and pepper, add the remaining oil, if necessary. The mixture should be smooth wiht course bits of pine nuts and no excess oil.
To serve, garnish the soup in the tureen with a dollop each of the sour cream and pesto. Surround the dollops with basil leaves. Pass the rest of the sour cream and pesto in small bowls.