Return the saucepan to the stove over medium-high heat.
Add some oil to the pan.
Cook the pork until it is brown and caramelised, breaking it up with a wooden spoon as you cook it.
Add the garlic and ginger, and cook for a few minutes until fragrant.
Add the ground Sichuan peppercorns which you set aside earlier.
Add the doubanjiang, chilli flakes, soy sauce, dark soy sauce, Chinese black vinegar, stock cube (or powder), and water.
Mix everything together and simmer gently for about 10 minutes.
Stir through enough cornflour slurry (cornstarch slurry) until the sauce has thickened nicely.
Taste the sauce for seasoning. If the sauce is too strong, dilute it with some water.
Remove the tofu from the packaging.
Place the tofu onto a chopping board or large plate.
Slice the tofu into large chunks (the tofu will break up later in the sauce, so starting with large pieces is better).
Carefully slide the tofu into the sauce. I like to leave the tofu sitting on top of the sauce, but you can stir the tofu into the sauce, bearing in mind that silken tofu will break up easily. If you are using a firmer tofu, stir it through the sauce so that it is well-coated.
Place the lid on the saucepan.
Turn the stove down to low-medium heat.
Simmer gently for about 5 minutes, or until the tofu is warmed through.
Garnish with spring onions (scallions) before serving.