Cantonese Char Siu Bao (Steamed BBQ Pork Buns)

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Make dim sum-style Char Siu Bao at home with this streamlined recipe. These Cantonese BBQ pork buns are incredibly light, fluffy, and cake-like texture that you will absolutely enjoy!

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If you’ve been following my blog for a while, you probably know that I already have a char siu bao recipe made with my everyday steamed bun dough. That version is soft, fluffy, slightly chewy, and incredibly versatile. It’s still one of my favorite doughs because I use it for all kinds of steamed buns. But if you’ve ever ordered char siu bao at a Cantonese dim sum restaurant, you’ve probably noticed they’re quite different.
Instead of being soft and chewy, traditional Cantonese char siu bao have an incredibly light, airy, almost cake-like texture with beautiful signature cracks that bloom across the top during steaming. For years, I’ve wanted to recreate that exact texture at home.
After experimenting with several recipes and techniques, I finally settled on this version. It keeps the process much simpler than many traditional recipes while producing the texture my family loves most. These buns are wonderfully fluffy, feather-light, slightly sweet, and filled with juicy char siu filling. They have become our preferred version whenever we’re craving dim sum-style BBQ pork buns.

What Makes Cantonese Char Siu Bao Different?

Unlike many Asian steamed buns that use a straightforward yeast dough, Cantonese char siu bao has a very unique texture.
The dough is:
1. Extra light and airy
2. Slightly sweet
3. Soft with a delicate cake-like crumb
4. Characterized by cracks on top after steaming. Those cracks are not mistakes—they’re actually one of the defining characteristics of traditional Cantonese char siu bao.

Why You’ll Love This Recipe

1. The sponge dough creates incredible flavor and a soft, airy crumb without requiring a traditional lao mian starter.
2. Baker’s ammonia produces the signature light, cake-like texture that’s difficult to achieve with baking powder alone.
3. The streamlined method is much easier than traditional dim sum recipes while still delivering authentic results.
4. The filling is rich, glossy, sweet-savory, and stays beautifully juicy inside the buns.
5. These buns freeze exceptionally well, making them perfect for meal prep or quick breakfasts and snacks whenever you’re craving dim sum at home.

A Little History: Traditional “Old Dough” (Lao Mian) Method

Before commercial yeast became widely available, many Cantonese dim sum shops relied on an old dough starter known as lao mian (老面).
Lao mian works similarly to a sourdough starter, except, you do not accumulate any discard. Instead of making a fresh dough every day, a portion of fermented dough from the previous batch was saved and mixed into the next day’s dough without discarding anything. Over time, this continuously refreshed starter developed a rich population of wild yeast and beneficial bacteria. The dough was then mixed with fresh flour, sugar, and other ingredients before being allowed to ferment again.
Because lao mian continues producing acid during fermentation, the dough traditionally had to be neutralized with alkaline ingredients before steaming. Experienced dim sum chefs carefully adjusted the alkalinity by feel and experience. Too little alkali and the buns could taste sour. Too much and the buns developed an unpleasant alkaline flavor and yellowish color. It was a process that required years of practice and tremendous skill. Today, most home cooks (and even many restaurants) simplify the process by using commercial yeast instead of maintaining an old dough starter.

How This Dough Differs from My Everyday Steamed Bun Dough

I still absolutely love my regular steamed bun dough, and I use it all the time for savory buns, sweet buns, and almost every steamed bun recipe on my blog.
Here’s how the two compare.
1. My Regular Steamed Bun Dough: Soft and fluffy, slightly chewy, versatile for almost any filling, smooth surface after steaming, and easier ingredients that most home bakers already have.
2. This Dim Sum-Style Dough: Extremely light and airy, delicate cake-like texture, slightly sweeter, beautiful cracked tops, uses baker’s ammonia for authentic texture, and is closer to what you’ll find at Cantonese dim sum restaurants.
Neither dough is better—they simply create different styles of steamed buns.
If you’re looking for an everyday steamed bun recipe, my original dough is still the one I recommend.
But if you’ve been chasing that authentic dim sum restaurant texture with feather-light crumbs and signature cracked tops, this recipe is the closest I’ve come after years of testing.

Why I Use a Sponge Dough Instead

This recipe uses what’s called a sponge (or starter) dough. A portion of the flour, water, and yeast are mixed together first and allowed to ferment for 1 to 2 hours before the remaining ingredients are added. This shorter fermentation offers several benefits:
1. It develops more flavor than mixing everything at once.
2. It creates a lighter crumbs
3. It gives the dough better structure.
4. It produces a texture that’s much closer to traditional dim sum char siu bao without maintaining a lao mian starter.
It’s a great compromise between authenticity and convenience.

The Secret Ingredient: Baker’s Ammonia (Ammonium Carbonate)

One ingredient that really makes a difference is baker’s ammonia, also known as ammonium carbonate. I’ll admit—I was hesitant to buy it at first because I wasn’t sure I’d use it often. Now I keep it stocked in my pantry. It creates an incredibly light, fluffy interior that baking powder alone simply can’t replicate.
When exposed to high heat, baker’s ammonia breaks down into carbon dioxide, ammonia gas, and water vapor. Those gases expand rapidly, giving the buns their airy, delicate texture. The ammonia completely evaporates during steaming, leaving behind no chemical taste or smell—as long as the buns are steamed properly over high heat. The result is that signature fluffy, almost cake-like crumb that makes Cantonese char siu bao so unique.

Isn’t Baker’s Ammonia Just for Cookies?

5. Not at all. Although baker’s ammonia isn’t as common today, it has been used for generations in European and Asian baking. It’s especially popular for:
1. Old-fashioned crisp cookies
2. Crackers
3. Traditional biscuits
4. Some Chinese pastries
5. Cantonese steamed buns like char siu bao
It creates a lighter texture than baking powder in recipes that are relatively low in moisture.

Where Can I Buy Baker’s Ammonia?

I was pleasantly surprised to find mine at Michael’s in the cake decorating section. You can also find it at: Baking supply stores, Some specialty grocery stores, Online retailers. A small container lasts quite a long time because each recipe only uses a tiny amount.

Tips for Using Baker’s Ammonia Successfully

1. Crush it first. Baker’s ammonia can form small hard pellets during storage. Crush it into a fine powder before mixing it into the dough so it distributes evenly.
2. Always steam over high heat. Unlike regular steamed buns, this dough needs vigorous steam. High heat ensures the baker’s ammonia completely decomposes into gas and fully evaporates. Insufficient heat may leave behind an unpleasant ammonia smell.
3. Steam long enough. Don’t shorten the steaming time. A full 18–20 minutes allows enough time for the ammonia to dissipate while fully cooking the buns.
4. Don’t worry about the smell while steaming. You may notice a brief ammonia smell escaping from the steamer. That’s completely normal. It’s actually a sign that the ammonium carbonate is breaking down as intended. Once the buns are finished steaming properly, that smell disappears.
5. Use only the recommended amount. More is definitely not better. Too much baker’s ammonia can produce an overly strong smell and negatively affect the texture.

Why This Dough Cracks on Top

Many people think the cracked tops are accidental, but they’re actually intentional. The dough is shaped differently from pleated steamed buns. Instead of creating decorative pleats, the dough is wrapped in a special way to encourage cracking during steaming. During steaming, the rapid expansion from the yeast, baking powder, and baker’s ammonia causes the top to naturally split open into beautiful cracks. That’s exactly the look you’ll find in many Cantonese dim sum restaurants.

Ingredients & Substitutions

1. Cake flour: Cake flour gives these buns their signature soft, delicate, cake-like texture. Its lower protein content produces a much finer crumb than all-purpose flour. I don’t recommend substituting all-purpose flour if you’re aiming for authentic dim sum-style char siu bao because the buns will be noticeably chewier.
2. Water: Water hydrates the sponge dough and develops the gluten needed to support the airy structure. Room temperature water works well.
3. Instant yeast: Instant yeast ferments the sponge and provides much of the rise. There’s no need to bloom it first. If using active dry yeast, dissolve it in the water first and allow it to become foamy before mixing with the flour.
4. Double-acting Baking powder: Baking powder gives the buns an extra lift during steaming, creating a lighter texture. Make sure your baking powder is double-acting kind for the best result.
5. Sugar: Sugar lightly sweetens the dough, which is characteristic of Cantonese char siu bao. It also feeds the yeast during fermentation.
6. Baker’s ammonia (ammonium carbonate): This is the key ingredient for achieving the incredibly light, airy, cake-like texture found in traditional dim sum char siu bao. Crush it into a fine powder before adding it to the dough to prevent lumps. Do not substitute with baking soda or more baking powder. While you can omit it if necessary, the texture will be noticeably different and the buns won’t have the same light crumb or characteristic cracked tops.
7. Salt: Salt enhances the flavor while helping strengthen the dough.
8. Lard: Lard contributes richness, tenderness, and a soft mouthfeel. Traditional Cantonese recipes almost always use lard. You can substitute vegetable shortening if preferred.
9. Char siu (Chinese BBQ pork): Homemade or store-bought char siu both work well. Dice it into small pieces so the filling is easy to wrap and evenly distributed in every bite.
10. Garlic, onion, and ginger: These aromatics build a flavorful base for the filling. Finely chopping them helps them blend smoothly into the sauce.
11. Cooking oil: Used for sautéing the aromatics before adding the sauce.
12. Oyster sauce: Adds savory richness and depth that complements the sweet char siu.
13. Soy sauce: Provides seasoning and balances the sweetness of the filling.
14. Hoisin sauce: Gives the filling its signature sweet-savory flavor with a hint of spice.
15. Dark soy sauce (optional): Mainly used to deepen the color of the filling. The recipe is still delicious without it.
16. Sesame oil: Adds a nutty aroma that rounds out the filling.
17. Water: Loosens the sauce and creates enough moisture for a juicy filling.
18. Red yeast rice powder (optional): Adds the traditional reddish hue often seen in restaurant-style char siu filling without affecting the flavor very much.
19. Cornstarch slurry: A mixture of cornstarch and water thickens the filling into a glossy consistency that stays inside the buns instead of leaking during wrapping.

Tips for Success

1. Chill the filling thoroughly before wrapping. Cold filling is much easier to work with and helps prevent the dough from becoming sticky.
2. Don’t make the filling too wet. It should be thick enough to hold its shape on a spoon. A runny filling makes the buns difficult to seal.
3. Keep the dough covered whenever you’re not actively working with it. Even a few minutes of exposure can dry out the surface.
4. Leave the center of the wrapper slightly thicker than the edges. This helps support the filling and prevents the bottom from becoming too thin after wrapping.
5. Seal the dough tightly so the filling doesn’t leak during steaming.
6. Resist the urge to peek while steaming. Opening the lid too early can cause the buns to collapse.
7. Steam over high heat for the full recommended time. This is especially important when using baker’s ammonia, as it needs sufficient heat to fully decompose and evaporate.
8. If you’re using a metal steamer, wrap the lid with a clean kitchen towel to prevent condensation from dripping onto the buns.
9. Transfer the finished buns to a cooling rack immediately after steaming so the bottoms don’t become soggy.

Variations

1. Substitute the char siu filling with barbecue chicken for a lighter option.
2. Replace the pork with finely diced roasted mushrooms and extra onions for a vegetarian version.
3. Add finely diced water chestnuts to the filling for extra crunch.
4. Make mini char siu bao for dim sum parties or appetizers by dividing the dough into 18 to 20 smaller portions.

Storage

Allow the buns to cool completely before storing. Refrigerate leftovers in an airtight container for up to 3 days.For longer storage, arrange the cooled buns in a single layer on a baking sheet and freeze until firm. Transfer them to a freezer-safe bag or container. They keep well for up to 2 months.

Reheating

Steam refrigerated buns for about 5 minutes until heated through. Frozen buns can go directly into the steamer without thawing. Steam over high heat for about 5 to 7 minutes or until hot all the way through.

Frequently Asked Questions

1. Can I omit the baker’s ammonia?
   Yes, but the buns won’t have the same light, cake-like texture or authentic cracked tops. They will still taste good but will be closer to regular steamed buns.
2. Will the buns taste like ammonia?
   No. When used in the correct amount and steamed over high heat for the full cooking time, the ammonia completely evaporates, leaving no unpleasant taste or smell.
3. Can I use all-purpose flour?
   I don’t recommend it for this recipe. Cake flour is one of the main reasons these buns have such a delicate crumb. All-purpose flour will produce a denser, chewier bun.
4. Why didn’t my buns crack?
   Several factors can affect cracking, including dough consistency, shaping, steam intensity, and using baker’s ammonia. High heat and the correct dough formulation are both important for achieving the signature split tops.
5. Can I make the filling ahead of time?
   Absolutely. In fact, I recommend making it a day ahead. The filling tastes even better after the flavors have had time to meld, and it’s much easier to wrap when thoroughly chilled.
6. Can I freeze these?
   Yes. These buns freeze beautifully and reheat directly from frozen, making them perfect for quick breakfasts, snacks, or whenever a dim sum craving strikes.

Check out this Soft and Fluffy No-Yeast Chinese Steamed Buns. These are so good and super easy to make! I have used this no-yeast steamed buns recipe to make char siu bao and all kind of steamed buns with sweet or savory fillings.