Place oil in a large saucepan. Add onions and garlic. Saute over medium heat until translucent (approx 2-3 minutes).
Mix the bouillon and water until partially dissolved. Add bouillon mixture and all remaining ingredients to the saucepan. Stir well using a wire whisk.
Simmer, uncovered, 25-30 minutes to allow flavours to meld. Stir frequently. Refrigerate overnight in a non-metallic container. Sauce is best if prepared a day before using. Keeps well, refrigerated, for 1 week.
NOTE: Best if refrigerated overnight before using!