The success of this soup depends on really good canned tomatoes and long, slow simmering so that all the flavors meld and mingle. The recipe is adapted from one in Cowgirl Creamery Cooks (Chronicle Books).
1. Heat a large pot over medium-high heat. Pour in oil, then add onion, carrots, garlic, 1 tsp. salt, the red pepper flakes, and bay leaves. Cook, stirring occasionally, until vegetables have softened and onion is translucent, 6 to 8 minutes. "It's important to cook your onions before you add liquid. Otherwise they won't melt in a simmering pot; they stay fibrous," advises Smith.
2. Add tomatoes, crushing them up with your hands, plus their juice and 2 cans water. "Canned whole tomatoes are usually higher quality than chopped," Conley says. "But chopped are okay in a pinch." Bring soup to a simmer and add half of oregano. Decrease heat to very low and simmer, partly covered, 2 hours. About 20 minutes before soup is done, add remaining 1/2 tsp. salt and the remaining oregano.
3. Remove bay leaves and blend soup until smooth. Add a bit of water if the soup looks thick, and strain if you want it silky smooth.
4. Serve soup topped with crème fraîche and chives.