Known as assam heh in Malaysia, this speedy stir-fry packs tons of umami, as well as salty, sour and fruity notes. Our version was inspired by one taught to us by Pearly Kee, proprietor of Penang Homecooking School and author of “A Nyonya Inheritance.” We favor peeled shrimp, but unpeeled work well, too, as the shells capture the sauce; they require just an extra minute or so in the pan. We replaced the kecap manis—a type of sweet soy sauce—with regular soy plus brown sugar to mimic its dark, caramel flavor. Look for tamarind sold as a dark, firm block packed in plastic; it might be labeled “wet” or “seedless,” but will require both hydrating and straining. Serve with coconut rice and spicy sambal.