Refrigerate this soup and the caviar in separate covered containers for up to 3 days. When reheating the soup, stir in vegetable stock to thin as desired.
The common black olive or Mission olive is a ripe green olive that often obtains its characteristic color and flavor from lye curing and oxygenation. Olives that are tree ripened turn dark brown or black naturally. The majority of these olives are used for oil but the rest are brine- or salt-cured and are usually packed in olive oil or a vinegar solution. The Greek Kalamata and the French Nicoise are two of the more popular imported ripe olives.