1) Heat 2 tablespoons of the olive oil in a large skillet. Add the garlic and cook until barely golden. Remove the garlic, and set it aside.
2) Working in batches, add a single layer of beef cubes to the skillet and sear on all sides, adding additional oil when necessary. Remove each batch with a slotted spoon, and sprinkle with black pepper. Leave any remaining oil in the skillet, and set it aside.
3) In a large soup pot, bring the stock or broth to a simmer. Add the browned beef and rinsed barley, cover, and return to a full simmer. Reduce heat and cook gently for about 1 1/2 hours.
4) Return the skillet to medium heat and add 2 tablespoons of olive oil, if there wasn't any left over from the beef. Heat and add the onion, celery, carrots, and potatoes.
5) Stir in the oregano and thyme. Cover the skillet and cook over very low heat for about 15 minutes.
6) Transfer the vegetables to the simmering soup, then add the chopped tomatoes and the reserved garlic. Simmer for 15 minutes before serving.
Yield: 12 to 13 cups, 8 to 12 servings.