Finely chop garlic, ginger and green onion. Cut tofu into 1 inch cubes.
In a frying pan, add in cooking oil. Cook garlic and ginger until fragrant.
Add Sichuan Doubanjiang stir until fragrant.
Add 1 cup of water. Add tofu. Season with soy sauce, salt, ground Sichuan peppercorn and a pinch of sugar.
Let everything simmer for 2 minutes. Add in corn starch water 1 spoonful at a time. When the sauce is thick enough, stop adding starch water and turn off the heat.
Serve ma po tofu in a bowl and top with ground Sichuan peppercorn and green onion.