Add the chilli flakes, salt, sugar, mushroom powder, soy sauce, vinegar, sesame seeds and chopped peanuts to a large heatproof bowl.
Stir everything together and set the bowl somewhere safe. Once the hot oil is poured over, it may splatter (we place ours inside the kitchen sink).
Add oil, shallots, garlic, ginger, cinnamon, star anise and peppercorns to a saucepan.
Set it over medium-low heat. Let everything bubble away gently for 13-15 minutes, giving it a stir now and then. The goal is golden blonde, not brown, and definitely not burnt.
Pour the hot oil directly onto the chilli base. Be careful, it will sizzle and bubble.
Let it cool completely before jarring. Store it in the fridge for up to a month.
