Cut the tofu into medium cubes. Boil water in a pot and add some salt. Blanch the tofu in the salty water for 2 minutes. Drain. Heat some vegetable oil in a frying pan. When the oil is half heated (warm), sauté the beef to half cooked. Heat the oil again. When the oil gets warm, sauté the spicy soybean paste until there is an aroma. Add the fermented soybean and the chili powder, sauté until the red spicy oil appears. Add some water and the tofu, cook for 3 minutes. Add the soy sauce, the beef and the garlic sprout, cook for 2 minutes. Dress the materials with the starch blended with water. Turn off the fire when the sauce gets thick. Dish up and spread the Chinese prickly ash powder on the top.