Most soups from Southeast Asia are tart, spicy, and fishy. An important ingredient in many is tamarind. Tamarind gives the soup its sour and slightly sweet flavoring. Generally, its good practice to use fresh ingredients but I’ve found the tamarind soup base to be very full flavored, more so than using fresh tamarind. This soup base is available at most Asian Grocery stores. I find that a pack like this would last me about 5-8 meals.