Description
These soft, fluffy Korean soboro buns are topped with a crumbly peanut streusel and optionally filled with sweet red bean or pineapple-coconut filling. This version uses tangzhong for extra tenderness and an overnight stiff sourdough starter for flavor, while maintaining a light, airy crumb.
Important Note: Tangzhong-based enriched doughs behave differently than lean sourdough doughs. For the best texture, this dough should be fermented at a warm temperature. Cold bulk fermentation is not recommended.
Ingredients
Stiff Sourdough Starter
- 60 g bread flour
- 30–33 g water (50-55% hydration)
- 12 g mature sourdough starter
Tangzhong
- 80 g water
- 16 g all-purpose flour or whole wheat flour
Peanut Streusel
- 75 g unsalted butter, room temperature
- 64 g peanut butter
- 90 g brown sugar
- 1 large egg yolk
- 1 teaspoon vanilla extract
- 140 g all-purpose flour
- 1 1/2 teaspoons baking powder
- 1 tablespoon cornstarch
Dough
- All of the tangzhong
- 120 g milk, lukewarm
- 1 large egg (about 50 g)
- 36 g sugar
- 4 g salt
- 210 g all-purpose flour
- All of the stiff sourdough starter
- 1/2 teaspoon instant yeast (optional but recommended)
- 28 g unsalted butter, very soft
Filling (Choose One or Omit)
Sweet Red Bean Paste
Option 1: Quick Method
- 430 g (14.3-ounce) can sweetened, mashed red beans
Option 2: From Dried Beans
- 1 cup (200 g) dried adzuki beans
- 1/4 cup (55 g) brown sugar, packed
- 1/4 cup (85 g) honey
- 1/2 teaspoon (3 g) salt
Pineapple-Coconut Filling
- 4 ripe pineapples, peeled and finely processed
- 200 g granulated sugar (adjust to taste)
- 65 g desiccated coconut
- 3–4 whole cloves
- 1 small cinnamon stick
- Pinch of salt
For Coating the Buns
- 1 cup water
- 1–2 tablespoons cornstarch
Instructions
1. Prepare the Stiff Sourdough Starter (10–14 Hours Ahead)
Mix the bread flour, water, and mature sourdough starter into a firm dough. Cover and ferment at room temperature until it is slightly domed and fragrant.
2. Make the Tangzhong
Whisk the water and flour together in a small saucepan. Cook over medium heat, whisking constantly, until it is thick and smooth. Transfer the roux to a bowl and cool to room temperature.
3. Prepare the Peanut Streusel
Cream the butter and peanut butter until smooth. Mix in the brown sugar, egg yolk, and vanilla. Add the flour, baking powder, and cornstarch, and mix until it is crumbly. Cover and set aside at room temperature.
4. Prepare the Filling (If Using)
Sweet Red Bean Paste (From Dried Beans)
Soak the dried adzuki beans overnight, at least 8–10 hours. Drain and rinse well.
Place the soaked beans in a pressure cooker and add about three times their volume of water. Add a small pinch of baking soda. Pressure cook until the beans are soft and slightly mushy. Drain the beans, rinse once, and reserve about 1 cup of the cooking liquid.
Return the cooked beans to the pot. Add the brown sugar, honey, and salt, and stir until incorporated. Add 1/2 cup of the reserved bean liquid.
Place the pot over medium heat. Bring to a boil, then reduce to a simmer and cook for 8–10 minutes, stirring occasionally, until thick and chili-like in consistency. Add more bean liquid as needed to adjust the texture.
Transfer to a clean bowl and cool completely before using. The red bean paste can be made up to 3 days in advance and stored in the refrigerator.
Pineapple-Coconut Filling
Combine all filling ingredients in a saucepan. Simmer over low heat until it is thick and jam-like. Remove the cloves and cinnamon stick and cool completely before using.
5. Mix the Dough
In the bowl of a stand mixer, whisk together the tangzhong and milk until smooth. Add the egg and sugar and mix well. Tear the stiff sourdough starter into pieces and add to the bowl.
Add the flour, salt, and yeast, if using. Mix on low speed until a shaggy dough forms. Cover and let rest for 10 minutes to allow the flour to hydrate.
6. Knead
Knead on medium-low speed for 5 minutes. Add the butter gradually and continue kneading for another 3–5 minutes, until the dough is smooth, elastic, and slightly tacky but not sticky.
7. Bulk Fermentation (Warm Only)
Place the dough in a lightly greased bowl. Cover and ferment at warm room temperature for 60–90 minutes, until increased in volume by about 1½ to 1¾ times.
Do not refrigerate the dough at this stage.
8. Divide and Rest
Turn the dough out onto a lightly floured surface. Divide into 10–12 pieces, depending on preferred bun size.
- For 10 buns: 55–58 g each
- For 12 buns: 45–48 g each
Shape into loose balls, cover, and rest for 15 minutes.
9. Fill and Shape
Flatten each piece gently. Add filling according to bun size and seal carefully.
- For 10 buns: 12–15 g filling
- For 12 buns: 10–12 g filling
Why less filling works better: Using a smaller amount of filling allows the dough to expand more freely in the oven, resulting in a lighter crumb.
10. Apply Streusel
Whisk the water and cornstarch together to make a thin slurry. Dip the smooth top of each bun into the slurry, then press generously into the peanut streusel. Place 5–6 buns on each parchment-lined baking sheet.
11. Final Proof
Cover loosely and proof in a warm place for 40–50 minutes, until the buns are puffy and slightly jiggly.
12. Bake
Bake in a preheated 375°F (190°C) oven for 13–15 minutes, rotating pans halfway through. Cool on a wire rack.
Notes
Prep Tip
This recipe has several components. To make bake day easier, prepare the fillings a day or two in advance. The buns are also excellent without any filling. The peanut streusel is flavorful enough to stand on its own.
Make-Ahead Notes (Optional)
Short cold pause: After partial bulk fermentation, the dough may be refrigerated up to 10 hours. Bring fully to room temperature before dividing and shaping.
Overnight shaped proof: Shape and fill the buns, then refrigerate overnight. Allow to proof at room temperature until puffy before baking.
Storage and Freezing Notes
Storage:
Soboro Ppang is best eaten the day it is baked, once cooled to room temperature. Leftover buns can be stored in an airtight container at room temperature for up to 1 day, or refrigerated for up to 2 days.
Freezing Baked Buns:
Fully baked and cooled buns freeze well, with or without filling. Wrap individually and freeze for up to 1 month. Thaw at room temperature, then rewarm briefly in a low oven to refresh the texture.
Freezing Unbaked Buns:
Shaped buns without streusel may be frozen after shaping. Freeze until firm, then store in an airtight container for up to 1 month. Thaw overnight in the refrigerator, bring to room temperature, add the streusel, proof until puffy, and bake as directed.
To reheat: Warm briefly in a low oven until just heated through to restore softness.
- Category: Sweet Buns
- Method: Sourdough
- Cuisine: Korean