Vegetarian Chilled Yellow Tomato Soup

1 tablespoon olive oil, plus 1 teaspoon
2 large onions, chopped
3 1/2 lbs yellow tomatoes, chopped,8 cups
salt
freshly ground black pepper
1 ripe avocado
1/4 cup chopped fresh cilantro
2 tablespoons fresh lime juice
1 tablespoon chopped shallots
1/3 cup seeded and diced ripe tomatoes
1/3 cup yellow pear tomatoes, halved
2 small tomatillos, husked and diced

In a large saucepan, heat 1 tablespoon oil over medium heat.
Add onions and cook, covered, stirring occasionally until translucent, 4 to 5 minutes. Add chopped yellow tomatoes; cook, uncovered, until pulpy, about 20 minutes. In a blender or food processor, puree tomato mixture in 2 batches.
Press through a fine sieve into a large bowl, discarding skins and seeds.
Season with salt and pepper. Cover and refrigerate until chilled, at least 2 hours or overnight. Just before serving, peel and pit avocado.
In a small bowl, mash avocado, chopped cilantro, lime juice and shallot into a coarse puree. Season with salt and pepper.
In another small bowl, toss red tomato, yellow pear tomatoes and tomatillos with remaining 1 teaspoon oil. To serve, ladle soup into 6 chilled soup plates.
Place a scoop of avocado puree in the center and surround with some of the tomato mixture.