Tangzhong Black Bean Buns （湯種黑豆包）
Bread kneading is quite a rewarding process, from the smell of yeast crawling in and out of the corners of your house, to the brawny gains built massage after massage, albeit only in my dominant arm.
I developed this recipe taking inspiration from Kimchimari's Milk Bread recipe, which used a tangzhong bread making technique. Tangzhong is a bread making method that was initially brought to pass by the Japanese, yet in the meantime it radiated throughout both eastern and southern Asia by the Chinese. And I can confirm-- this method does quite the trick! Such a process sees eye to eye with the basic principles of hydration in bread making (cue the finicky squabbles over the perfect baker's percentage). In a typical bread making recipe, most of the starch gelatinization occurs in the oven, by which the imbibed starch granules expand under heat and eventually explode upon maximum swelling. Free water molecules enveloped by the encircling protein matrix vaporize, consequently giving rise to the bread's structure, as well as the delectable crumbs we eat for breakfast. However, via tangzhong, some starch gelatinization occurs prior to the dough's entry into the oven, with around 60% of the dough hydrated in advance (I calculated my recipe's hydration percentage to be somewhere around 59%). With more starch granules retaining sufficient stores of water, once introduced to a complete heating process, a dough made under the tangzhong method would utilize this added moisture and its vaporization to fully stretch the gluten strands, thusly yielding a light, pillow-y bread texture.
Alright, enough of my bread rant and more of my outlandish endeavors. As always, I wanted to put my own spin on this delicacy based on present day constraints. Because I could not get my hands on the oh-so greatly venerated red beans, I decided to substitute them with a black bean filling instead, which, afterall, pack more antioxidants and fiber than do red beans. Finally, because my oven was feeling lonely (it's been awhile since I baked!) I veered off the traditional steaming course and reconciled with my oven.
Incorporating the tangzhong breadmaking technique, these buns are tender and fluffy, and the gentle fragrances of the black bean filling only adds an extra dimension of heavenly relishing!
Recipe
Ingredients
Cuisine: Asian-fusion
Servings: 16 buns
Level: Hard
Servings: 16 buns
Level: Hard
Prep time: 2 hrs 15 min
Cook time: 17 min
Total time: 2 hrs 32 min
Ingredients
For tangzhong:
Instructions:
- 1/4 cup flour
- 1 cup water
For buns:
- 4 cups flour
- 3/4 cup white granulated sugar
- 1/2 tablespoon salt
- 2 teaspoons yeast
- 1/2 cup milk* (1 additional tablespoon for egg wash)
- 1 large egg (+ 1 additional egg for egg wash)
- 1/2 cup vegetable oil
For bean filling:
- 2 cups black beans, cooked (+ approx 1/2 cup residual aquafaba or remaining bean water used to cook the legumes)
- 1 tablespoon dried osmanthus flower leaves
- 1/2 cup white granulated sugar
- 1/2 cup brown sugar
- 2 tablespoons honey
- oil (for greasing saucepan)
- 1/4 cup cornstarch
- Preheat oven to 350 degrees Fahrenheit.
- Prepare tangzhong by heating flour and water in a medium sized saucepan on LOW heat while stirring continuously until a thick, gelatinized slurry forms (3-5 minutes). Store in fridge for at least 1 hour until further use.**
- In a large bowl, whisk together flour, sugar, salt, and yeast.
- Gradually stream in milk, stirring continuously with a pair of chopsticks (or using bread machine). Add in egg and tangzhong, and continue stirring mixture. Once dough fully coalesces, begin kneading until smooth.
- Add in oil and continue to knead until all oil is absorbed and dough becomes springy.***
- Cover bowl with saran wrap, followed by a towel or lid, and set outside under sunlight or the middle rack of oven with light on.
- Allow dough to rise for 1 1/2 - 2 hours. Meanwhile, prepare bean filling. In a food processor, add in black beans and the leftover aquafaba. Add in osmanthus flower leaves, white granulated sugar, brown sugar, and honey. Pulse until combined.****
- Generously grease a deep saucepan with oil (you may use same the saucepan as previously used in step 1). Transfer pulsed bean filling into saucepan on MEDIUM-LOW heat. Add cornstarch and stir continuously for around 10-15 minutes. When mixture becomes thick and difficult to ply, remove from heat.
- Generously grease a large tin tray for baking.
- Remove dough from fermentation phase and knead until smooth and shiny. The dough should be springy and sturdy at this point. Roll dough into logs and divide into 16 pieces in totality.
- Knead each individual ball of dough, this time stretching and pulling from its centre, and then rolling the ends on top of one another until a spherical shape renders.
- Taking one of the balls, use the palm of your hands to press into the dough 2-3 times until it flattens. In the center, place a modest amount of the bean filling. Pinch the edges of the dough to envelope the bean filling (you may also use a baozi folding technique). Roll the dough on each side a few times to render a smooth, spherical shape. Repeat process for each individual cut of dough.
- Place each bun onto the greased baking tray. Let the buns rest for a second rising phase for 15-20 minutes. After so, beat one large egg and brush each bun with an egg wash solution composing of egg and milk.
- Bake for 10 minutes with heat on, and let rest in oven for 2 minutes with heat off.
- Remove from oven, and enjoy your tender tangzhong black bean buns! Serve while warm or store in an airtight container/ziplock bag at room temperature. After 2 days, store in fridge; when buns are desired for consumption, heat in microwave for approximately 10-15 seconds with a wet paper towel layered on top of it.
Notes:
*1%, whole milk, and nut milks will all achieve the same results.
Liquid should be at room temperature (60 deg F- 80 deg F or 20 deg C- 30 deg C)
**tangzhong can also be achieved by mixing flour and water in a bowl and heating in microwave for 15 second intervals and stirring in between, ensuring slurry is homogeneously gelatinized.
Before using tangzhong, ensure slurry is at room temperature. Put it differently, remove slurry from fridge around 1 hour before use.
***test the readiness of your kneaded dough by tearing a piece of your dough and stretching it to see how easily it tears when stretched. If it tears too easily, continue to knead until gluten strands strengthen. The piece of dough should also be flexible and extend as a thin, strong membrane. Stop kneading once this is achieved.
****based on personal preferences, some may consider not thoroughly pulsing the bean mixture, as whole beans may add an extra dimension of texture in the end product. That said, if one prefers a smoother filling, by all means, pulse until fully homogenized.
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