1. Heat the oil in a 6-quart saucepot over medium heat. Add the onions and garlic and cook until they're tender.
2. Stir the broth and potatoes in the saucepot and heat to a boil. Reduce the heat to low. Cover and cook for 30 minutes or until the potatoes are tender.
3. Pour 1/3 of the broth mixture into a blender or food processor. Cover and blend until smooth. Pour the mixture into a large bowl. Repeat twice more with the remaining broth mixture. Return all of the puréed mixture to the saucepot. Stir in the vinegar and cheese. Increase the heat to medium. Cook for 5 minutes or until the mixture is hot and bubbling. Season as desired.
4. Divide the soup mixture among 12 serving bowls. Top each with 2 teaspoons tapenade.
Tip: Serve with a hot crusty French baguette. For dessert serve with chocolate mousse pudding.