Soft, fluffy rolls with a naturally sweet purple sweet potato filling and a beautiful spiral shape—these steamed buns are both delicious and stunning.
How I discovered these purple beauties
I first made these when I had extra purple sweet potatoes, and I wanted to wrap their creamy sweetness in a soft, pillowy dough. The spiral shape looks stunning and makes these rolls feel extra special.
Lard in Chinese Cooking: Why I Love Using It
Let’s talk about lard—a humble yet incredibly powerful ingredient in traditional Chinese cooking that often gets overlooked.
I know it’s not as commonly used in modern kitchens, but when it comes to soft, fluffy doughs, lard really makes magic happen.
In Chinese pastry and bread-making, lard isn’t just for frying or adding richness. It’s prized for how it transforms the texture of dough. When added to flour, even in small amounts, it helps create dough that is:
- Soft and elastic
- Smooth and easy to knead
- Fluffy and tender after steaming
- Bright white in color
It’s a key ingredient in recipes like Peanut Sesame Buns, Chinese Golden Buns, and even Savory Tang Yuan.
If you’ve ever wondered why some steamed buns from traditional bakeries have that silky softness and perfect bounce—that’s often lard doing the heavy lifting.
And don’t worry—if lard isn’t available to you or if you prefer not to use it, unsalted butter or neutral vegetable oil (like sunflower or canola) make great substitutes.
Tip: Want to go the traditional route? You can make your own lard at home with just pork fat and a little time. I‘ve shared a full, step-by-step guide on rendering lard from scratch—it‘s simpler than it sounds and incredibly rewarding.
Filling Ideas: Beyond Purple Sweet Potato
While I used a purple sweet potato filling in this recipe for its beautiful color and naturally sweet, creamy flavor, you can easily switch things up based on what you have or love.
Here are a few of my favorite alternatives that pair beautifully with the soft steamed dough:
I’ve got a full detailed guide on how to make the perfect purple sweet potato paste from scratch—smooth, creamy, and just the right amount of sweet.
Ingredients
Purple Sweet Potato Filling
- 200g purple sweet potato (peeled weight, about 2–3 medium-sized)
- 20–30g white sugar (adjust based on sweetness of the sweet potato)
- 10g condensed milk (about 1 spoon; substitute: 15g milk powder + 5g warm water)
- 20–30ml milk (optional, to adjust texture)
Dough
- 300g all-purpose flour
- 3g white sugar (helps activate the yeast)
- 3g instant dry yeast (about ½ teaspoon)
- 10g lard (about 1 spoon; can be replaced with unsalted butter or vegetable oil)
- 160ml warm water (30–35°C in winter; room temp in summer)
Instructions
- Make the Purple Sweet Potato Filling
Steam the sweet potatoes: Peel and slice them into thick rounds. Steam over boiling water for 15–20 minutes, until a chopstick goes through easily.
Mash and mix: While still hot, mash the steamed sweet potato. Mix in sugar and condensed milk. If too dry, gradually add milk in 2–3 additions (5–10ml each) until smooth and moldable like thick mashed potatoes.
Cool: Let the filling cool to room temperature before using.
- Make the Dough
Mix ingredients: In a large bowl, combine flour, sugar, and yeast. Add lard, then pour in warm water. Stir with chopsticks until shaggy.
Knead: Knead by hand for 5–8 minutes into a smooth dough. If sticky, dust lightly with flour—but add only a little to keep it soft.
Divide dough: Cut into 8–10 equal pieces (each about 40–50g).
- Shape and Fill
Roll and fill:
Roll one piece into a ball, then flatten into an 8–10cm round wrapper (edges slightly thinner).
Place 25g filling in the center, pinch closed like a bun, then gently flatten.
Roll into a tongue shape (12–15cm long, 6–8cm wide).
Cut and roll into spirals:
Cut evenly spaced strips across the surface (don’t cut through).
Flip over, press one edge thinner, roll up from the other end.
Pinch both ends to seal into a spiral.
- Proof and Steam
Rise: Place shaped rolls on a steamer lined with oil or parchment, leaving 2cm space between each. Cover and proof at room temperature for 30 minutes (in winter, add warm water to the steamer to help proof). They’re ready when puffy and bounce back slowly when pressed.
Steam:
Start from cold water. Bring to a boil on high heat, then steam over medium for 15 minutes.
Turn off heat and let sit for 3 minutes before opening the lid (prevents shrinking).
Serve: Let cool slightly. Enjoy while warm.
Frequently Asked Questions
What if I don‘t have lard?
You can substitute it with unsalted butter or vegetable oil in equal amounts.
How should I store leftovers?
Let them cool completely, then store in an airtight container in the fridge for up to 2 days. Reheat by steaming for 5–7 minutes.
How to Make Purple Sweet Potato Swirl Buns
Ingredients
Purple Sweet Potato Filling
- 200 g purple sweet potato peeled weight, about 2–3 medium-sized
- 20 –30g white sugar adjust based on sweetness of the sweet potato
- 10 g condensed milk about 1 spoon; substitute: 15g milk powder + 5g warm water
- 20 –30ml milk optional, to adjust texture
Dough
- 300 g all-purpose flour
- 3 g white sugar helps activate the yeast
- 3 g instant dry yeast about ½ teaspoon
- 10 g lard about 1 spoon; can be replaced with unsalted butter or vegetable oil
- 160 ml warm water 30–35°C in winter; room temp in summer
Instructions
Make the Purple Sweet Potato Filling
- Steam the sweet potatoes: Peel and slice them into thick rounds. Steam over boiling water for 15–20 minutes, until a chopstick goes through easily.
- Mash and mix: While still hot, mash the steamed sweet potato. Mix in sugar and condensed milk. If too dry, gradually add milk in 2–3 additions (5–10ml each) until smooth and moldable like thick mashed potatoes.
- Cool: Let the filling cool to room temperature before using.
Make the Dough
- Mix ingredients: In a large bowl, combine flour, sugar, and yeast. Add lard, then pour in warm water. Stir with chopsticks until shaggy.
- Knead: Knead by hand for 5–8 minutes into a smooth dough. If sticky, dust lightly with flour—but add only a little to keep it soft.
- Divide dough: Cut into 8–10 equal pieces (each about 40–50g).
Shape and Fill
- Roll and fill:
- Roll one piece into a ball, then flatten into an 8–10cm round wrapper (edges slightly thinner).
- Place 25g filling in the center, pinch closed like a bun, then gently flatten.
- Roll into a tongue shape (12–15cm long, 6–8cm wide).
- Cut and roll into spirals:
- Cut evenly spaced strips across the surface (don't cut through).
- Flip over, press one edge thinner, roll up from the other end.
- Pinch both ends to seal into a spiral.
Proof and Steam
- Rise: Place shaped rolls on a steamer lined with oil or parchment, leaving 2cm space between each. Cover and proof at room temperature for 30 minutes (in winter, add warm water to the steamer to help proof). They're ready when puffy and bounce back slowly when pressed.
- Steam:
- Start from cold water. Bring to a boil on high heat, then steam over medium for 15 minutes.
- Turn off heat and let sit for 3 minutes before opening the lid (prevents shrinking).
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