Seared Fresh Sardines and Tomato Soup

Name: Seared Fresh Sardines and Tomato Soup
Ingredients: 1/2 cup plus 2 tablespoons olive oil, divided; 2 pounds fresh tomatoes; Kosher salt and freshly ground black pepper; 1 teaspoon sugar; Small bunch of basil, leaves separated from stalks; Small bunch of chives; 1 sweet onion, peeled and chopped; 1 fennel bulb, trimmed and chopped; 1 carrot, scrubbed and diced; 2 garlic cloves, minced; 4 cups chicken or vegetable stock; 2 tablespoons balsamic vinegar; 4 small fresh Atlantic herring or Mediterranean sardines, gutted, heads and fins removed, and butterflied (tails can be left on); 2 tablespoons crème fraîche for serving; 2 teaspoons salt-cured capers for garnish