Mapo tofu is a justly popular menu item in many Chinese restaurants. It is a quickly cooked dish of braised tofu with minced pork (sometimes beef) in a bracing spicy sauce made with fermented black beans and fermented broad bean paste, along with hot red pepper and Sichuan pepper. This meatless version with fresh shiitake mushrooms is completely satisfying, and surprisingly easy to make. For the best texture, use soft tofu rather than firm, taking care to cook it gently to keep it from crumbling.