We had this sauce everywhere in India, usually with samosas or tandoori. There are many variations.
I had a bunch of coriander to use up so made this sauce-it works well with both Indian and Mexican food.
Blitz together a bunch of coriander (including stalks), 1 green chilli, a garlic clove, 1/2 tomato, 1/4 red onion, 1/2 tsp cumin powder, a squeeze of lime juice, salt to taste.
If you like add some yoghurt