This is the signature dish of Sichuan cuisine. It is hot, simple, and rustic yet a showcase of sophisticated texture contrasts and forceful, hot, typical Sichuan spices. It is named after an apparently real restaurant cook in the Sichuan capital of Chengdu who invented it some time before the fall of the Qing dynasty in 1911. There are now many restaurants in Sichuan and elsewhere offering ma po dou fu in widely varying versions. This minimalist recipe is based closely on the one Fuchsia Dunlop learned during her studies at the Sichuan Institute of Higher Cuisine in Chengdu. If you recoil from fiery spicing, look elsewhere for dinner.