Cover 200 g dried chickpea with plenty of water and leave to soak for at least 8 hours or overnight. Drain and rinse thoroughly.
Transfer the soaked chickpeas to a pressure cooker with 500 ml water and salt to taste. Pressure-cook for 10 minutes (or simmer gently in a lidded heavy saucepan for 90 to 150 minutes) until completely tender.
Warm 4.5 g vegetable oil in a deep frying pan over medium heat. Tip in the spices for the paste and stir-fry for 1 to 2 minutes until fragrant. Transfer them to a blender or mortar along with 80 g grated fresh coconut and 264 g tamarind extract, then process to a smooth paste.
Pour the cooked chickpeas and their liquid into the pan. Stir in 600 g cubed potato, 1 g curry leaf, the turmeric, and additional salt if needed. Pour in up to 125 ml extra water if the mixture seems dry, then simmer uncovered for 7 minutes.
Fold in the blended spice paste and simmer for another 7 minutes until the gravy is well combined and slightly thickened.
Heat 9 g vegetable oil in a small pan over medium heat. Add the tempering spices and 0.5–0.8 g curry leaf, sizzling for roughly 1 minute until the mustard seeds pop. Pour the hot spiced oil immediately over the simmering curry, stir to combine, and remove from the heat.
Use equal dry weight; soak for 30 minutes instead of overnight. Cooks much faster and produces a softer, creamier texture rather than firm, whole beans.
Steep a tiny pinch (0.1 g per 2 g turmeric) in 2 tbsp warm water; use to match the rich golden hue. Contributes an aristocratic, honeyed floral flavour rather than earthy bitterness.
Use 50% to 60% of the weight, soaked in equal parts warm water for 15 minutes before grinding. Works well for chutneys, though texture is slightly finer and sweeter.
Use 1.2 times the weight in curries. Adds creamy richness and authentic flavour, but makes gravies smoother and eliminates the grated, chewy mouthfeel.
Use the same weight. The seeds are smaller and hotter; fry in hot oil until they pop, about 20–30 seconds, and reduce the heat if they darken too fast. The dish will be a little sharper.
Use 70% of the weight of whole seed, added with the other ground spices rather than fried whole. You lose the popping texture and the heat comes through more evenly.