Ma Doufu

Ma doufu and douzhi come from the very same process. When mung beans are ground and fermented to make starch noodles, the starch is drawn off; what is left splits into a thin sour liquid — douzhi — and a sunken green pulp, which, drained of its water, is ma doufu. Both carry the fermented tang of that shared origin. It was a poor man's dish, a way to turn the noodle-makers' cheap leftovers into something good — kin to luzhu, baodu and douzhi in the old Beijing repertoire of "the poor man's pleasures." Some say it goes back to early Ming, but that rests only on repeated recipe lore with no record behind it; it is safest called simply an old Beijing snack born in the noodle workshops.

A loose, soft mound of greyish-green pulp, glistening with fat, a red pool of chili oil sunk into the middle with flecks of dried chili. The texture is fine and tender, almost spreadable; the taste runs savory and oily with a low fermented sourness underneath, the snow vegetable adding salt and a little bite, the green soybeans a soft pop. Where you hit the lamb-tail fat, a small burst of richness comes through. It is an acquired taste, like douzhi — but a gentle one.

The sourness is no added vinegar — it is the natural product of fermenting the mung-bean pulp, the same fermentation that makes douzhi. The technique is patient frying: lamb-tail fat is diced and rendered, then the pulp is fried slowly over low heat, stirred without stop until most of its water is gone and the surface erupts in a fine honeycomb of bubbles. Snow vegetable and soybeans go in, the fat scraps fold back, and a saucer of fresh-fried chili oil is poured into a well pressed in the center. The lamb-tail fat is the whole point — it gives this lean grey pulp a meaty richness, and stands up to the long frying; skip it and the dish is no longer authentic.