The magic ingredient here is Josey Chu’s own Sambal Nyonya: a deep red paste made from chili peppers, onions, tamarind, vinegar, sugar and molasses for a rich, complex heat. The flavors combine beautifully with the last fall tomatoes and tender bok choy. Chu has been crafting her own Southeast Asian sauces under the Madame Chu label since 2017. It’s available at Metcalfe’s Market, Willy Street Co-op, Viroqua Co-op and Chu’s website, but if you can’t find it, gochujang, hoisin sauce or harissa paste could all work in a pinch.