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. Add the garlic, ginger, and green onion, cook and stir until fragrant. Add the doubanjiang and fermented black beans, cook and stir for another minute. Add the blended spices and cook for about 10 minutes. Add the sugar, Shaoxing wine, and mushroom powder. Stir until dissolved. Remove from heat and let cool for 10 to 20 minutes. Blend until the oil is emulsified.
Pour the hot pot base into a large heat-proof container. Top with dried chilis and crushed peppercorns. Freeze overnight. Divide the base into individual portions and store 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.
To use the hot pot base, add it to the hot pot and pour in 4 to 5 cups of broth. Heat over medium-high heat and stir to dissolve the soup base. Ready to cook when the soup is boiling.