These purple sweet potato steamed buns are soft, fluffy, and beautifully colored with the nutritious root vegetable!
Steamed buns (or mantou) are a soft type of steamed bread originating from Northern China. They are rather neutral in flavor, making them a diverse food that can be paired with savory or sweet foods. Common pairings with steamed buns include pork belly, soft crab, and sweetened jams or pastes. Traditional steamed bun is made with just 3-4 ingredients: flour, water or milk, yeast, and salt (optional), and is conveniently cooked in a steamer rather than an oven! This is pretty great since stovetop cooking is used commonly throughout the world whereas ovens are not as common, due to limited space or other reasons. The plain, white mantou has evolved throughout the years with people adding flavors, nuts, fruits, seeds, and shaping them into animation characters! There are some extravagant steamed bun out there that are simply too beautiful to eat.
Don’t worry though, this recipe is rather simple and forming the buns are rather therapeutic. For these purple sweet potato buns, I am using typical steamed bun ingredients plus the addition of purple sweet potato to create bicolored buns. Not only does the sweet potato add color, but it also adds nutrients and flavor. The steamed buns are neutral in flavor, neither sweet nor salty, and have a very subtle sweet potato taste.
What type of purple sweet potato do you use?
There are 3 common types of purple sweet potatoes:
- Okinawa: light purple flesh, white/tan skin, typically most expensive, native to Japan (~ $3/lb.)
- Stokes: darker purple flesh, brown skin, typically cheaper than Okinawa sweet potato, native to the U.S. (~$2/lb.)
- Charleston: deep and dark purple flesh, dark grey/purple skin, cheapest, native to the U.S. (~$$1.50/lb)
I grew up only eating the Okinawa potato, which can be found in Asian grocery stores or specialty grocery stores like Whole Foods, but I actually found out that my local grocery store began to sell Charleston sweet potato, so I happily bought them to experiment with as they are cheaper. I find that all 3 potatoes taste extremely similar. You may notice slight differences in texture and flavor when eating them alone, but because the recipes utilizes the potatoes in a dough, there is really no difference. I used the Charleston sweet potato for this and it yields a darker purple color than a Okinawa or Stokes sweet potato would, which I liked.
How do you shape the mantou?
I was going for a kind of floral shape that I saw a steamed bun artist do, but mine didn’t look like his at all. Instead, I sort of created my own shape and the outcome looks quite nice! The shapes and patterns aren’t quite uniform since I’m no steamed bun artist, but I am getting the hang of it. For the pattern, the only tools you need are a rolling pin, knife or pastry scraper, and a chopstick. Please watch the video to see how the buns are shaped exactly.
Steamed bun cooking tips:
- Use all-purpose flour for steamed buns as it contains the proper percentage of gluten for a soft, yet firm bread.
- Use a stacked steamer to steam more buns at a time.
- Bamboo steamers steam better than metal ones. The bamboo steamer absorbs condensation whereas the metal steamer accumulates condensation on the top and the liquid drops down on the buns. Thus, the buns steamed in a metal steamer tend to be too moist. I use this Bamboo Steamer.
- Use a Thin rolling pin to easily roll out the dough.
- For the 20 min. resting period of the buns, place the steamer over a pot with cool water. This cool water is the water that will be used to steam.
- Bring the water to a boil, and then place the steamer on top to steam. Do NOT bring the water to a boil while the steamer is on top.
- Steam the buns on high heat.
- Once the buns are steamed, turn the heat off and do not remove the lid off immediately. Allow the buns to rest for 5 min. and then remove the lid. If you don’t do so, the rapid temperature change will cause the buns to collapse and become wrinkly.
- Milk should be lukewarm.
- Rest the dough in a warm place, such as a slightly heated oven. I turned my oven on for 1 min. and then turned it off to create the warm environment.
Purple Sweet Potato Steamed Buns
yield: 8 large or 10 medium buns
total cook time: 1 hr. 30 min.
For purple dough:
- 125 g. or 1 c. purple sweet potato, uncooked and diced into 1 in. cubes (any type of purple sweet potato works. Please see notes above on purple sweet potatoes)
- 20 g. or 1 1/2 tbsp. granulated sugar
- 62 g. or 1/4 c. + 1/2 tsp. warm milk (any fat percentage)
- 140 g. or 1 c. + 1 tbsp. all-purpose flour
- 3 g. or 3/4 tsp. dry active yeast
For white dough:
- 125 g. or 1/2 c. + 2 tbsp. warm milk (any fat percentage)
- 2 g. or 1/2 tsp. dry active yeast
- 10 g. or 2 tsp. granulated sugar
- 200 g. or 1 2/3 c. minus 1 tbsp. all-purpose flour
- Place the sweet potatoes into a small pot and cover with water. Boil the potatoes, covered, for 15 min. or until tender.
- Drain the potatoes and place them in a small bowl. Mash the sweet potatoes with a form until a fine paste forms. (Note: the water will be purple. This can be saved and used as natural food coloring for other recipes if desired)
- Add the sweet potato mash, 20 g. granulated sugar, at 62 g. warm milk in. large bowl. Whisk until incorporated.
- Add in the flour and yeast and knead for 10 min. Add additional milk or flour if needed. Place the purple dough into a bowl and cover. Rest in a warm place for 35 min.
- To make the white dough, combine milk, yeast, and sugar. Whisk until the yeast and sugar dissolved.
- Add the flour and knead for 10 min. Add additional milk or flour if needed. Place the white dough into a bowl and cover. Rest in a warm place for 35 min.
- Both doughs should double in size. Punch the air out of each doughs and transfer them to a clean surface that is generously floured.
- Roll each dough into a 8-9 in. log. Cut both logs into 8 pieces for large buns and 10 pieces for medium buns.
- To form 1 bun, roll 1 piece of purple and white dough into a circle 4 in. in diameter. Stack the purple dough on top and cut the circle into quarters. Stack the quarters on each other and use a chopstick to make the design as shown in the video.
- Place the bun on a small piece of parchment paper and place in steamer. Repeat for the rest of the buns.
- Rest the buns for 20 min. in the steamer, covered, over cool water. The buns will grow in size.
- After the buns have risen, bring water in the steamer to a boil on high heat and then place the steamer on top. Steam the buns on high for 18-20 min.
- Turn the heat off after 20 min, and allow the buns to rest for 5 min before removing the lid. The buns are ready to be served!
*Nutrition facts are estimates.
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