Bring a pot of salted water to a gentle boil. Carefully slide the tofu cubes in and blanch for 2 minutes. Drain and set aside; this helps the tofu hold its shape.

Heat the vegetable oil in a wok or large frying pan over medium-high heat. Add the minced shiitake mushrooms and stir-fry for 3-4 minutes until they are browned and slightly crispy.

Push the mushrooms to one side of the pan. Add the fermented bean paste, ginger, and garlic to the oil. Stir-fry for 1 minute until fragrant and the oil turns red.

Pour in the vegetable broth, sugar, soy sauce, and half of the ground Sichuan peppercorns. Stir to combine and bring the sauce to a simmer.

Gently slide the blanched tofu into the sauce. Simmer for 3-5 minutes so the tofu absorbs the flavors. Avoid stirring vigorously to prevent breaking the tofu; instead, swirl the pan.

Stir the cornstarch slurry and pour it slowly into the pan. Simmer for another minute until the sauce thickens and clings to the tofu.

Remove from heat. Sprinkle with the remaining Sichuan peppercorns and green onions before serving hot over rice.