The Chinese pork bun (kao bao) beats your everyday hamburger at its own game. It substitutes a baby cheek of golden brioche for mass-produced white bread, cubes of lacquered roast pork for the pre-formed patty and salty-sweet russet custard for the usual Heinz products.
The burger is a stalwart protein delivery device, a noble foil to the French fry, an encapsulation of the poetry of the backyard barbecue, but it's not what you'd call clever.
Kao bao ("baked bun") is the Hong Kong version of the more traditional cha siu bao ("roast pork bun"). The two buns contain the same barbecued pork filling but call for entirely different doughs and cooking methods.
Cha siu bao is a steamed bun made of low-gluten cake flour. The cake flour is chemically transfigured during the steaming process by an indispensable trace of baker's ammonia, which explains the otherwise unobtainable whiteness and springiness of these buns. Reflecting the British colonial influence in Hong Kong, kao bao is baked. It utilizes high-gluten bread flour enriched with egg and plenty of butter (an ingredient foreign to traditional Chinese cuisine). Its John Bull forebears include the Sally Lunn and the "hot cross bun" of Mother Goose fame.
Dim Sum House, an enormously popular dumpling palace not far from RDU airport (100 Jerusalem Drive, Suite 104, Morrisville, 919-380-3087), offers fine versions of both buns along with dozens of other labor-intensive nibbles served in a giddy kaleidoscope of plates and carts.
"A superior baked pork bun has a soft, melting texture," says chef-owner Aquan Jiang. "It should almost dissolve in your mouth, and it should have an irresistible fragrance of butter."
Jiang, whose oil-scarred forearms attest that he—and he alone—does the cooking at Dim Sum House, says that he learned the kao bao recipe from the Hong Kong dim sum master under whom he apprenticed at Toronto's Dragon Dynasty.
"I serve this bun in an homage to my master and because Westerners love it so much," says Jiang.
The wonder of the kao bao is that it will inevitably—let me repeat: inevitably—appeal to the Krispy Kreme clamorers of the kiddy set. As soft and sweet as any doughnut, the kao bao might as well come in a green dotted box.
Pork marinade and glaze
2 lbs. pork butt (or other cut of well-marbled pork)
2 Tbsp. rice wine
1 1/2 tsp. sugar
1 tsp. kosher salt
6 drops red food coloring
6 Tbsp. honey
1 1/2 tsp. water
1 cup water
1/4 cup sugar
2 Tbsp. soy sauce
1 1/2 Tbsp. oyster sauce
6 drops red food coloring
2 Tbsp. cornstarch + 2 Tbsp. water
1 envelope (8 grams) active dry yeast (not instant yeast) + 1/2 tsp. (3 grams) sugar
1/4 cup (40 grams) water, warmed to 100–110 degrees
3–3 1/2 cups (454 grams; 1 lb.) bread flour (see note)
13 Tbsp. water (163 grams) water, at room temperature
1/2 cup (115 grams) sugar
6 Tbsp. (84 grams) unsalted butter, at room temperature
1 large egg
1/2 cup honey (see note)
2 tsp. water
Marinate and roast the pork: Combine the rice wine, sugar, salt and food coloring in a large bowl; reserve the honey. Cut the pork into 1/2-inch-thick slices and thoroughly coat with the marinade. Cover and refrigerate for at least 2 hours. Grill or broil the pork until cooked through and lightly charred. Combine the honey and water. Glaze the pork with the honey-water mixture and briefly return to the grill or oven, allowing the honey to caramelize. Dice into 1/4-inch cubes and set aside.
Prepare the pork filling: Combine the water (1 cup), sugar, soy sauce, oyster sauce and food coloring in a medium saucepan or wok. Bring to a boil. Add the pork to the sugar-soy mixture. Combine the corn starch and water (2 Tbsp.) and mix to the consistency of a thin paste. Slowly add the cornstarch paste to the bubbling pork mixture, swirling to incorporate. The pork mixture will quickly thicken. The consistency should be viscous but still runny (like thick gravy), and the pork should be lightly coated (neither dry nor immersed). The color should be an appealing russet-red. Set aside to cool.
Prepare the dough: Combine the yeast, sugar (1/2 tsp.) and warm water (1/4 cup) in a small bowl. Rest for 10 minutes, or until the yeast has begun to froth and billow. Meanwhile, combine the flour, water (13 Tbsp.), sugar (1/2 cup), butter and egg in the bowl of a stand mixer. Add the activated yeast mixture. Using a dough hook, knead at medium-low speed (Kitchen Aid Level 4) for 12 minutes. The dough should be glossy, loose and elastic. It should be sticky but not so sticky that it won't cleanly pull away from the side of the bowl. Add trace amounts of flour or water to achieve the correct consistency.
Assemble: Pluck a small piece of dough (35 grams) and form into a ball (1 1/2-inch diameter). Place the ball on a well-floured surface and roll flat to a diameter of 4 1/4 inches. To avoid a bottom-heavy bun, roll the perimeter of each round more thinly than the center. Place a heaping spoonful (30 grams) of pork at the center of each round. With the left thumb, roll a bit of the perimeter over the right thumb. Withdraw the right thumb and press to form a pleat. Repeat until the bun has been entirely pleated and closed. (YouTube abounds in demonstrations; enter keyword "wrap pork buns"). Place each bun pleat-side down on a baking sheet covered with parchment paper, leaving 2 1/2 inches between buns to allow for expansion.
Proof and bake: Heat the oven to 100 degrees. Insert the buns, leaving the door slightly open. Proof for 1 hour, or until the buns become rounded, smoothed and puffed. Remove the buns from the oven and increase the temperature to 350 degrees. Bake for 15 minutes, or until the buns turn light golden brown. Remove and immediately brush with the honey-water mixture. Due to the sugar content of the dough, the buns are apt to burn—keep your eyes on them.
Bread flour has more protein (4 grams per 1/4 cup) than all-purpose flour. King Arthur Unbleached Bread Flour is ideal. Look for the blue-trimmed bag in the local supermarket. Measuring flour by volume is notoriously inaccurate. One pound of flour measures 3 1/2 cups loosely packed, but 3 cups more densely packed. A baker without a scale is like a doctor without a stethoscope, an accountant without a calculator, a fireman without a ladder—you get the idea.
Chef Jiang glazes his buns with maltose syrup. Honey is a flavorful and texturally correct substitute.
This article appeared in print with the headline "Behold the pork bun."