Aloo Posto

Method

1. Rinse 2 tbsp of white poppy seeds and soak them in just-boiled water for 20 minutes, until the seeds swell and crush easily between finger and thumb.
2. Drain the seeds well and grind them in a small wet grinder or stone mortar with 1 green chilli, a pinch of the salt and 1-2 tablespoons of fresh water, working in short bursts for 3-4 minutes until you have a smooth, pale, cream-thick paste with no grittiness. Scrape it out and set aside.
3. Set a kadai or heavy frying pan over medium-high heat and warm 2 tsp of mustard oil until it just begins to smoke and loses its raw pungency. Lower the heat to medium, add 0.25 tsp of nigella seeds and 1 green chilli, slit lengthways, and let them crackle for about 20 seconds.