Kao Fu (Shanghai Braised Gluten)

Wheat gluten puffs have a cellular, sponge-like structure created by deep-frying. Soaking and squeezing removes the frying oil and collapses the internal air pockets, creating a dense, absorbent matrix that can take in braising liquid with remarkable efficiency. By the end of cooking, each piece is saturated with sauce, which is why kao fu delivers such concentrated flavor despite being made from a relatively bland starting ingredient.

The combination of light and dark soy sauce creates both flavor and color. Light soy sauce provides the primary saltiness and savory depth, while dark soy sauce adds the characteristic deep brown color and a touch of sweetness from its added molasses or caramel.

Rock sugar dissolves more slowly than granulated sugar, which is actually an advantage in braising. It allows the sweetness to build gradually and produces a cleaner, less cloying result. It also contributes to the sauce's gloss.

The dish is served cold because the flavors are more distinct and balanced at lower temperatures. Warm, the sweetness can seem cloying; cold, it is tempered and elegant.

• Fried gluten puffs: If unavailable, fresh baked wheat gluten (kao fu) can be found in some Chinese markets. Cut into cubes and proceed without the soaking step.
• Lily buds: If unavailable, omit them rather than substitute. Their flavor is unique, and the dish will still be delicious without them, just slightly less complex.
• Wood ear mushrooms: Fresh or dried shiitake mushrooms can substitute, though the texture contrast will be different.
• Peanuts: Edamame or fried tofu puffs are alternatives. Some versions include bamboo shoots for additional crunch.
• Vegan: Use vegetarian oyster sauce in place of regular oyster sauce if your recipe includes it. This version as written is already vegan.

Kao fu is traditionally served as part of a cold appetizer spread at the beginning of a Shanghai-style meal. It pairs well with other cold dishes: smoked fish, marinated jellyfish, or dressed tofu skin. It also works as a side dish alongside congee, or as a component in a rice bowl topped with other braised items. In a Western context, it can serve as an unusual and flavorful appetizer or snack.

This dish is specifically designed to be made ahead. Store in an airtight container in the refrigerator for up to 1 week. The flavor improves over the first 2 to 3 days as the sauce continues to penetrate the gluten and the ingredients meld. Serve cold or at room temperature. If you prefer it warm, reheat gently in a small pot with a splash of water. Freezing is possible for up to 2 months, though the wood ear mushrooms may soften slightly.

Si xi kao fu (四喜烤麩, "four-joys braised wheat gluten") is the Shanghainese cold appetizer of spongy wheat gluten (kao fu) braised with wood ear mushrooms, dried shiitake, lily buds (jin zhen), and peanuts in a sweet-savory sauce of soy sauce, sugar, Shaoxing wine, and aromatic spices, then chilled and served at room temperature as part of the traditional Shanghainese cold-dish lineup that opens a formal meal. The dish belongs to the broader Shanghai leng cai (cold dish) tradition and is one of the most strongly Shanghainese vegetarian preparations, served at homes across the city during Lunar New Year and at Shanghai restaurants worldwide as a permanent menu fixture.

The signature ingredient is kao fu, a spongy form of wheat gluten that begins as raw seitan (the protein extracted from wheat flour by washing out the starch), is then leavened with yeast and steamed until it has the porous, almost bread-like structure that defines the form. The spongy texture is critical to the dish: the kao fu acts like a sponge for the braising liquid, absorbing the sweet-soy sauce into its many tiny air pockets and releasing it in the mouth when chewed. The cooked kao fu is tender, slightly elastic, and dramatically more flavorful than the same volume of plain seitan.

The technique tears the kao fu into rough bite-sized pieces (cutting with a knife is discouraged since the torn surfaces absorb sauce better), pan-fries the pieces briefly to color the surface, then braises everything together for thirty to forty minutes in the sweet-soy sauce until the mushrooms and lily buds soften and the kao fu turns dark mahogany. The dish is removed from the heat, allowed to cool to room temperature, and traditionally served from a small glass or ceramic bowl as part of a cold-dish lineup that also includes drunken chicken (zui-ji), smoked fish, sweet-and-sour radish, and other Shanghai cold appetizers. The dish keeps well in the refrigerator for several days and improves slightly as the flavors meld.