1 cup chopped onion
4 cloves garlic — pressed
1 tablespoon vegetable oil
2 chiles — minced
1 teaspoon ground cumin
1/2 teaspoon dried oregano
3 1/2 cups chopped fresh tomatoes
3 cups vegetable broth
1/3 cup fresh lime juice
salt — to taste
In a medium soup pot, saute the onions and garlic in the oil until the onions are translucent. Add the chiles, cumin, and oregano, and saute for a few more minutes. Add the chopped tomatoes and sprinkle with a little salt. Cover the pot and cook gently until the tomatoes begin to release their juices. Stir occasionally. This will take longer with winter tomatoes than with summer ones. Add the stock and simmer, covered, for about 15 minutes. Add the lime juice and salt to taste.
Sever topped with crumbled tortilla chips. Garnish with finely chopped cilantro, if desired.