This sour-salty soup was made for those late-season tomatoes on your countertop about to go bad. They get jammy while the fish poaches. And go ahead, add some greens. Use shrimp! This soup is flexible.
Step 1
Heat oil in a medium pot over medium. Add shallots, garlic, lemongrass, and chilies and cook, stirring occasionally, until aromatics start to soften but have not taken on any color, about 5 minutes. Add tomatoes and cook, smashing and stirring, until tomatoes have burst and fallen apart and mixture is slightly thickened, about 5 minutes.
Step 2
Pour 5 cups cold water into pot and bring to a boil. Reduce heat to medium-low so broth is at a bare simmer.
Step 3
Add fish to pot; season lightly with salt (you’ll finish soup with fish sauce). Cook until fish is opaque and cooked through, about 4 minutes. Remove from heat; add lime juice and fish sauce. Taste and season with more salt and/or fish sauce if needed. Stir in herbs and ladle into bowls.