Drain the liquid from the tofu. Use a sharp knife and cut the tofu block into 1/2-inch cubes and set aside.
Place the broth and tofu cubes in a large pot. Bring it to a simmer and let them cook for about 5 minutes over medium-low heat. Turn off the heat and let them stand while you prepare the rest. This step ensures that the tofu absorbs the flavor and it gives the tofu a nice texture
Cooking:
Preheat a large wok/skillet over medium heat. Add 1 Tbsp of oil and add the pork and breaking up the meat with wooden spoon. Continue to cook for about 5 minutes until the meat turns color and is cooked through. Remove the pork from the wok/skillet but leave the oil on the wok/skillet
Add the rest of the oil. Add garlic, ginger, Sichuan peppercorns, Sichuan chili flakes, doubanjiang into the wok/skillet and cook over medium heat for about 3 minutes. Take care not to burn the chili flakes and peppercorns
Add the precooked ground pork back to the pan and stir to combine with the doubanjiang mixture
Add the broth and tofu you prepared earlier, hoisin sauce, sesame oil, and the ground pork to the wok and bring to a gentle simmer for about 2 minutes. Have a taste and adjust to your preference. Prepare the cornstarch solution by mixing the cornstarch with water
Drizzle the cornstarch solution to the wok and gently stir until the sauce starts to thicken.
Garnish with the chopped green onion. Transfer the mapo tofu to a serving platter and serve immediately
Leftovers:
Leftovers taste even better the next day. They can be kept in the fridge for about 2-3 days. I do not recommend freezing because the texture of the tofu will change and no longer be smooth and silky
Reheating:
Simply reheat the portion you want to eat in a pan over medium-low heat until heated through. You may need to add a splash of water to loosen up the sauce if it gets too thick