Step 1

Prepare a steamer for steaming. Bring the water to a boil over high heat. Meanwhile, while wearing gloves, pinch off the stems from 1 1/2 ounces dried erjingtiao chilies and 1 1/2 ounces dried chaotianjiao chilies and shake out the seeds. Rinse the chilies. Cut any longer erjingtiao chilies into smaller pieces.

Step 2

Place the chilies in a single layer in the steamer basket (steam in batches if needed). Cover and steam until the chiliies are plumper in texture but not wet, about 3 minutes. Remove the steamer basket from the steamer and let the chilies cool completely, about 20 minutes. Meanwhile, prepare the aromatics.

Step 3

Place 2 whole star anise, 2 tsaoko pods, 2 bay leaves, 2 pieces dried orange peel, 2 pieces Chinese liquorice, 2 pieces of cassia bark or 1 cinnamon stick, 5 whole cloves, 1 teaspoon red Sichuan peppercorns, 1 teaspoon cumin seeds, and 1/2 teaspoon fennel seeds in a small bowl. Slice a 1-inch piece of ginger. (No need to peel.) Trim and coarsely chop 2 medium scallions and 1 small red or yellow red onion. Thinly slice 10 garlic cloves.

Step 4

Transfer the cooled chilies to a food processor fitted with the blade attachment. Process into chili flakes, scraping down the sides occasionally, about 2 minutes. Transfer to a bowl. Add 2 tablespoons white sesame seeds, 2 tablespoons kosher salt, and 1 teaspoon MSG, if using.

Step 5

Heat 3 cups rapeseed oil in a wok or wide sauté pan over medium-low heat until 240 and 250°F. (You can test the oil by adding a piece of ginger, which should bubble immediately, but gently.) Add the spices, ginger, scallions, and onion. Let the aromatics slowly fry and release their water content, infusing the oil. Keep an eye on the bubbling, which should always be gentle, and use a spatula to move things around to prevent burning, removing any burned bits immediately with a strainer. After 20 to 35 minutes, the onion and scallions should look shriveled and may be slightly toasted and the oil should be very fragrant. Scoop out and discard all the aromatics with a heatproof fine-mesh strainer.

Step 6

Maintaining a temperature of 240 to 250°F, add 1/3 cup roasted soybeans if using to the oil. They will sink, so use a spatula to move them around, making sure they don’t burn, and cook for 3 minutes. Ad1/2 cup skinless peanuts if using, and fry for 1 minute, moving everything constantly. The peanuts should not be rapidly browning — if they are, lower the heat.

Step 7

Add the garlic. Once the garlic starts taking on the barest golden hue, after about 5 minutes, add the chili flake mixture. Turn the heat off and continue to stir constantly down to the bottom of the pan for 2 to 3 minutes more. The crispy bits will finish toasting in the residual heat and the oil will turn red. Taste and season with more salt, powdered Sichuan peppercorn, MSG, or sugar as needed. Let cool completely, then spoon into jars.