Vegan Sour Tomato Broth with Vegetables

Sinigang is sinigang so long as the broth is sour; there are no rules about which ingredients are used to bring that telltale shudder to the lips. So when I was in the Cayman Islands during the COVID-19 pandemic—far from home and family, waiting for a seat to open up on an evacuation flight—and woke up one morning longing for that hot sour broth, I decided to improvise. I was holed up in a hotel room under renovation, with only a bare-bones kitchenette: bar sink, self-heating tea kettle, mi