Put 1 cup of vegetable oil, 2 tablespoons of Sichuan peppercorns, 1 cinnamon stick, and 2 star anise in a small saucepan. Heat over medium-low heat to 325°F / 165°C, then turn off the heat.
After 6-7 minutes, lift out the spices and stir ¼ cup of red pepper flakes into the oil.
Heat 3 teaspoons of vegetable oil in a wok and brown 225g of ground pork. Add 2 teaspoons of sweet bean sauce, 2 teaspoons of Shaoxing wine, 1 teaspoon of dark soy sauce, and ½ teaspoon of five-spice powder. Cook until dry.
Transfer the pork to a bowl, leaving the oil in the wok. Stir-fry ⅓ cup of sui mi ya cai (preserved mustard greens) until fragrant.
Mix 2 tablespoons of tahini, 3 tablespoons of soy sauce, 2 teaspoons of sugar, ¼ teaspoon of five-spice powder, ½ teaspoon of ground Sichuan peppercorns, 2 finely minced garlic cloves, and half the chili oil.
Cook 450g of white noodles following the package, then blanch 1 small bunch of bok choy in the same water. Stir ¼ cup of hot noodle water into the sauce.
Divide the sauce between bowls and top with the noodles, bok choy, pork, and mustard greens. Toss before eating.
