Sichuan Chilli Oil

Steps

1. 1
   Grind half the Sichuan peppercorns. Put them in a heatproof ceramic or metal bowl with the chilli flakes, sesame seeds, salt and sugar, and stir in 2 tbsp of the oil, cold, so the flakes are moistened and less likely to scorch.
2. 2
   Pour the rest of the oil into a small pan and add the whole Sichuan peppercorns, star anise, cinnamon stick, bay leaves, spring onions, garlic and ginger.
3. 3
   Heat over medium-low heat for 15–20 minutes, so the aromatics bubble gently and turn golden brown without burning. This slow infusion is where the flavour comes from.
4. 4
   Strain out the aromatics and check the oil: at about 140°C a pinch of chilli flakes foams steadily without blackening. Much hotter oil burns the chilli and turns it bitter.
5. 5
   Pour the hot oil over the chilli mixture in two or three additions, stirring between them. It will foam up hard and turn deep red.
6. 6
   Leave to cool completely, then jar the oil with all its sediment. It is best after a day and keeps for two months in a cool, dark cupboard; stir the jar before use so every spoonful gets both oil and flakes.