Prep Jackfruit: Grease hands and knife with mustard oil. Peel outer skin and core of 500g raw jackfruit. Peel outer skin of seeds, slice seeds thin, and finely shred jackfruit flesh (lachha style).
Steam & Dry: Steam shredded jackfruit and seeds with 1 tbsp turmeric and ½ tbsp salt for 4–5 minutes until al dente. Drain well and sun-dry on a cotton cloth for 3–4 hours until moisture-free.
Roast & Grind Spices: Dry roast 3 tbsp saunf, 2 tbsp rai, 2 tbsp sabut dhania, 1 tbsp methi dana, and 1 tbsp jeera for 1 minute. Cool and coarsely grind.
Smoke Oil: Heat 1.5 cups mustard oil until the smoking point. Switch off the flame and cool to room temperature.
Mix & Marinate: In a dry bowl, combine dried jackfruit, 1.5 cups grated kairi, ground spices, 1 tsp kalonji, 1 tsp ajwain, 1 tbsp haldi, 2–3 tbsp red chilli powder, ½ tsp hing, 3 tbsp salt, and 1 tsp black salt. Pour cooled oil and mix well.
Sun Cure: Transfer to a dry glass jar, cover with a muslin cloth, and place in sunlight for 4–5 days. Stir daily. Top with extra oil if needed and store sealed.