Combine all the spices in a blender or food processor. Mix until the spices turn into small flakes but not powdered.
Heat the oil in a medium-sized pot or 9” deep pan over low heat until medium hot (if you add a small piece of garlic it should sizzle gently and not bubble furiously). Add the garlic, ginger, and green onion. Cook and stir until fragrant but not browned, about 2 minutes.
Carefully add the doubanjiang and fermented black beans to the oil. Cook and stir for another minute.
Add the blended spices. Cook, stirring frequently, for about 10 minutes. The oil should reach a vibrant orange-red color when it’s ready.
Add the sugar, Shaoxing wine, and mushroom powder. Stir until dissolved.
Remove the pan from the heat and let cool for 10 to 20 minutes (or longer if you have a non-heat proof blender).
Add the cooled hot pot base mixture to the blender. Make sure the lid’s air vent is open. Start from a low speed, gradually raising to medium-high speed, blending until the oil is emulsified, about 1 minute. The mixture will look cloudy once blended.
Carefully pour the hot pot soup base into a large heat proof tupperware. Top the whole dried chilis and crushed peppercorns evenly over the base for garnish. Cover the container and freeze overnight.
Once frozen, you can divide the base into individual portions by slicing it into 4 pieces. Then you can store each piece in a ziplock bag in the freezer for up to 6 months. Each block is good for a small hot pot, or one side of a hot pot with a divider.