How to Make It
In a large pot, heat the olive oil. Add the onion and garlic and cook over moderate heat, stirring occasionally, until
softened, 8 minutes. Add the tomatoes and their juices, the beets, carrots, 3/4 teaspoon of cumin and 1/4 teaspoon of cayenne. Season with salt and add enough water to cover the vegetables by 1 inch. Bring to a boil, cover partially and simmer over low heat until the vegetables are very tender, about 1 hour. Remove from the heat and let stand for at least 30 minutes to allow the flavors to develop.
Reheat the soup and season with salt, cumin and cayenne. Serve topped with a dollop of yogurt and a pinch of cumin.