If you don't have fermented soybean paste (huángdòu jiàng, 黄豆酱), Japanese miso or Korean doenjiang are acceptable substitutes in this recipe, since we just need the paste to help add salt, umami and depth of flavor to an already complex mixture. Pixian doubanjiang is also OK to use if you don’t mind also adding a little chili pepper, as is fermented tofu.