Char 400–600 g aubergine over a medium flame, rotating every 5–7 minutes, until the skin blackens and the flesh softens, 15–18 minutes.
Scrape off the aubergine skin and discard it. Mash the flesh with a fork and set aside.
Heat 27 g vegetable oil in a heavy-based saucepan over medium heat. Add 4 g green bird’s eye chilli, slit lengthways, and fry for a few seconds. Add 150 g onion and sauté for 8–10 minutes until softened and starting to colour.
Stir in 12 g garlic and cook for 20–30 seconds. Add 240 g tomato and fry for 5–6 minutes until softened. Add 5.2 g tomato purée and the ground spices for the sauce; cook for 1 minute.
Add the mashed aubergine and mix well. Cover and cook over low heat for 2 minutes.
Season with salt to taste. Scatter over 3 g coriander leaves, 15.3 g lemon juice and 6 g ginger julienne, then mix.
Use 80% of the weight, finely shredded and browned slowly with a pinch of asafoetida. Replicates the bulk and natural sweetness in gravies without allium.
Use 15% to 20% of the weight (about 1 g for every 5 to 6 g fresh cloves). Whisk into sauces; gives a savoury, toasted garlic flavour without raw pungency.
Use 40% to 50% of the fresh tomato weight mixed with a splash of water. Imparts a deeper red colour, thicker sauce, and slightly sweeter cooked flavour.
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 20% to 25% of the weight (1 g for every 4 to 5 g fresh). Stir into the gravy; adds peppery heat and warmth, though it misses the crisp, zesty kick of raw root.