📝 About This Recipe
Transport yourself to the bustling, wintry streets of Beijing with this authentic Kao Di Gua. These sweet potatoes are roasted until the natural sugars caramelize into a sticky, honey-like syrup and the skin becomes thin and papery. It is the ultimate Chinese 'Xiaochi'—a humble yet decadent snack that offers a smoky aroma and a velvety, melt-in-your-mouth texture that no modern oven can easily replicate without these specific techniques.
🥗 Ingredients
The Potatoes
- 4 large Chinese Yellow-Flesh Sweet Potatoes (Look for long, slender shapes for even roasting; also known as Beauregard or Jewel varieties)
The Secret Glaze (Optional Modern Twist)
- 2 tablespoons Maltose or Honey (Maltose provides the most authentic sticky shine)
- 1 tablespoon Warm Water (To thin the glaze)
- 1 teaspoon Toasted Black Sesame Seeds (For a nutty garnish)
Equipment & Aromatics
- 2 cups Coarse Sea Salt (Used as a heat bed to mimic the street vendor's charcoal drum)
- 2 pieces Star Anise (Placed in the salt bed for a subtle fragrance)
- 1 piece Cassia Cinnamon Stick (Optional, for the salt bed)
👨🍳 Instructions
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1
Select sweet potatoes that are similar in size and diameter to ensure they all finish cooking at the same time. Scrub them thoroughly under cold running water to remove any grit.
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2
Pat the potatoes completely dry with a kitchen towel. Do not skip this; dry skin is essential for the characteristic 'papery' texture of authentic street-style potatoes.
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3
Preheat your oven to 425°F (220°C). This high initial heat mimics the intense temperature of the traditional coal-fired clay barrels used by street vendors.
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4
Line a heavy baking sheet or a cast-iron skillet with a thick layer of coarse sea salt. Nestle the star anise and cinnamon stick into the salt; this creates a thermal mass that distributes heat evenly and prevents the bottoms from burning.
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5
Place the sweet potatoes directly onto the salt bed. Do not crowd them; ensure there is at least two inches of space between each potato for air circulation.
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6
Slide the tray into the center rack of the oven. Roast for 30 minutes without opening the door.
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7
Carefully flip each potato using tongs. You may notice the skin starting to puff away from the flesh; this is a perfect sign that the steam is separating the layers.
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8
Reduce the oven temperature to 375°F (190°C) and continue roasting for another 30-45 minutes. The lower temperature allows the sugars to undergo slow caramelization.
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9
Test for doneness by gently squeezing the potato with tongs. It should feel completely soft and 'hollow' inside, with some dark, syrupy liquid oozing out of the skin.
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10
Optional: In a small bowl, whisk the maltose and warm water. Brush a thin layer over the top of the potatoes and roast for an additional 5 minutes for a glossy, sweet finish.
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11
Turn off the oven and let the potatoes sit inside for 10 minutes with the door slightly ajar. This 'tempering' phase finalizes the texture.
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12
Remove from the oven and sprinkle with toasted black sesame seeds if desired. Serve immediately while steaming hot.
💡 Chef's Tips
Choose red-skinned, yellow-flesh potatoes as they have a higher sugar content and lower starch than white varieties. Never wrap the potatoes in foil; this steams the skin rather than roasting it, losing the authentic street-food texture. If your potatoes are leaking syrup onto the tray, don't worry—that is the 'honey' (sugar) caramelizing and is the best part. Use a bed of salt or a wire rack to ensure the bottom of the potato doesn't get soggy from its own juices. For an extra smoky flavor, you can finish the potatoes under the broiler for 2 minutes at the very end.
🍽️ Serving Suggestions
Pair with a cup of hot Roasted Oolong or Pu-erh tea to cut through the natural sweetness. Serve alongside other street snacks like Jianbing or spicy boiled peanuts. In Northern China, these are often enjoyed plain, held in a piece of paper to warm your hands. For a modern dessert twist, serve with a dollop of salted clotted cream or a drizzle of condensed milk. Enjoy as a healthy, fiber-rich breakfast on a cold morning.