Blitz ingredients in a food processor until it becomes a smooth, bright green sauce.

Use extra water to thin to a pourable consistency.

Put the tomatoes in a bowl. Sprinkle with pinch of salt, mix with your hands and leave to rest for 10 minutes (extracts a bit of juice, makes them juicier).

Drain the tomatoes. Mix with the onion in a serving bowl.

Drizzle dressing over the tomato salad.

Sprinkle with a pinch of garam marsala if desired.