1/2 cup preserved black beans, coarsely chopped
1/2 cup coarse-ground Sichuan or Korean red pepper flakes or dried red pepper flakes
1/4 teaspoon salt
1/4 teaspoon sugar
1 teaspoon ground, roasted Sichuan pepper or Chinese five-spice (optional)
1 1/2 cups peanut oil (China- or Taiwan-made, if possible)
1/4 cup finely diced shallots
Layer the dry ingredients in a heat-proof pint canning jar with a tight-fitting lid. Put black beans in first, then red pepper flakes, salt, sugar, and spice (if using). Set aside.
Add the oil to a small sauce pan and heat over a medium flame until hot. To test if hot, place one small shallot bit in the pan. If the pan is hot enough, the shallot bit will sizzle when it hits the oil.
Add the shallots and fry until they start to brown. Do not burn the shallots, but keep the oil at a fast bubbling simmer. When shallots are just golden, immediately transfer the hot oil and shallots to a glass measuring cup. Immediately pour the oil and shallots from the measuring cup over the jarred red pepper flake mixture. The flakes should fizz and sizzle, getting a light toast from the hot oil.
Allow to cool, then stir the mixture until well combined. Leave to cool and settle, and enjoy immediately or store in a cool, dark place. The mixture will taste best after it’s infused for a few days, and will last for roughly a month.