Spicy Tamarind Sauce

Combine water and tamarind pulp in a large saucepan. Bring to a lively simmer over high heat, reduce heat to maintain a simmer and cook, pressing on the pulp against the side of the pan, for 3 minutes. Let stand, covered, for 15 minutes.

Pass the tamarind mixture through a fine-mesh sieve in batches, stirring and firmly pressing on the solids, into a large bowl. Periodically scrape off the thick liquid clinging to the bottom of the sieve. You should get 2 1/2 to 3 cups. (Take your time with this process for the best results; it can take up to 10 minutes.) Whisk in fish sauce, brown sugar and Sriracha.