Heat a wok over low heat. Dry-toast the chilies for 1 minute, then deseed.
In a blender or food processor, grind the chilies into a powder.
In a dry wok over low heat, toast the cardamom, fennel seeds, sesame seeds, and star anise for 2 minutes. Set aside.
Heat the oil in the wok to 130 degrees and infuse the ginger, star anise, cardamom, and fennel for about 3 minutes. Remove.
Heat the oil to 190 degrees.
In a bowl, combine the chili powder, Sichuan pepper, rice vinegar, salt, and sugar. Mound the mixture into a volcano shape, creating a well in the center.
Turn off the heat and pour in half of the oil through the well of the "volcano," stirring vigorously.
Wait 7 minutes, then pour in half of the remaining oil.
Wait another 5 minutes, then pour in the remaining oil.
Let cool to room temperature, then refrigerate to infuse overnight.
Transfer to a jar.
Notes
Keeps for up to 1.5 weeks in the fridge.I like to return all the dried spices (cardamom, star anise, fennel, sesame) to the oil to continue infusing, but adjust to your taste.You can substitute chili flakes for the dried chilies, but the flavor won't be exactly the same.