Green Tea Sourdough Bao (Steamed Buns)

The January topic for Sourdough Surprises is Bao, those filled and fluffy steamed buns that are often found on dim sum carts in Chinese restaurants. Years ago I baked some tasty Char Sui Bao (BBQ pork filled buns) for a Daring Cooks challenge, but for some reason never did revisit that recipe. Here was an opportunity to try again, to tweak the previous Bao recipe a bit by relying solely on my sourdough starter for the rise and steaming the buns instead of baking them. 

The change list expanded after spotting an intriguing photo for Green Tea Bao with Sweet Filling (here). Matcha powder? That was an unfamiliar ingredient, but several online sources mentioned grinding green tea leaves to substitute for the commercial product. I could do that. Instead of driving to Uwajimaya's I grabbed an old coffee grinder, a metal sieve and a canister of loose green tea for my DIY version of matcha. 

Sweet sourdough buns suggested a sweet filling, sweet but not so sweet as to overwhelm the tea taste. Flavor pairings suggested online included citrus, dark chocolate, nuts, various berries and mint. I pulled Nutella, minty dark chocolate chips, raspberry preserves, coconut shreds and ground walnuts out of the pantry to try different combinations.    

My starter was frothy and peppy but the oddly colored Bao dough rose very slowly overnight on its first rise. I began to have doubts: should I have added some commercial yeast, or at least tossed in a bit of baking powder? Too late to worry, just press on.

The dough was agreeable to work with, forming balls and rolling out easily. My pleating and pinching technique improved as I worked, and only the raspberry/ground walnut filling showed any signs of leakage later as the buns steamed. 

The second rise was nearly a non-event. I grew so impatient waiting for a doubling in size and finally moved on to steaming the buns. I rationalized "they are sweet dessert morsels, small will be just fine. Maybe they'll fluff and expand more as they steam... maybe... if I didn't rush them too early."

Mixed reviews on the fluff factor! The buns did increase in size as they cooked but never matched the desired light airiness of restaurant Bao. The texture was pleasant enough to enjoy whether served directly from the steamer or cooled and eaten hours later. 

Dark Chocolate Mint Morsels scored my vote for best chocolatey filling, sweet but masking any green tea or sourdough flavor.

Nutella with coconut shreds came in last place, somewhat flat tasting and definitely too sweet to play nicely with the flavors in the dough.

RL awarded top marks to the raspberry and ground walnut filling, but it had some disappointing leakage issues while steaming. 

I steamed the two remaining ping pong sized balls of dough without rolling and filling, an experiment to test the dough's texture and taste without the distraction of filling. At first bite a definite sourdough tang was apparent but I couldn't distinguish any green tea flavor. Evidently my DIY grinding of green tea leaves didn't come close to matching authentic matcha powder's taste or coloration. No problem, for consolation I ate the two unfilled buns with a bit of butter and quite enjoyed them. 

 Now I am looking forward to checking out the posts from other Sourdough Surprises Bao bakers. 

Green Tea Sourdough Steamed Buns

Dough Ingredients (for 10-12 small buns)

1/8 cup sugar
1/4 cup warm water
1/4 cup refreshed sourdough starter
1 medium egg, whisked to blend white & yolk
1 Tablespoon oil
1/2 teaspoon salt
1 Tablespoon Matcha powder (finely ground green tea leaves)
1 cup plus 2 generous tablespoons AP flour

Directions for the Buns:

1. Place the sugar and warm water in a small bowl; mix until sugar dissolves. Add sourdough starter and whisk to incorporate.
2. Sift flour into a larger bowl. Add starter mixture, egg, oil, salt and Matcha powder; stir to mix. Use your hands to bring the flour mixture together.
3. Place dough on a lightly floured surface and knead for 10 minutes or until smooth and slightly elastic.
4. Place in a lightly oiled bowl; cover with a damp cloth and leave to rise until doubled in size. This could take several hours to overnight depending on your starter. 
5. Once dough has doubled in size, punch down and divide into 6 portions; shape into round balls.
6. Use a rolling pin to roll a ball into a 2-inch disk. Then pick up the piece of dough and gently pull the edges to enlarge to a 3-inch diameter disk. The dough should be slightly thicker in the center.
7. Place a heaping tablespoon of filling on the dough circle. Gather the edges and seal the bun.
8. Place the bun, seal side down, on a baking tray atop a square of parchment paper. Cover with a cloth and continue with the rest of the dough. Let the buns rise until doubled in size. Remove the towel.
9. Carefully place some of the buns (still resting on their parchment paper squares) in a steamer basket, positioning them several inches apart to allow for spreading.
10. Place in a steamer for 10-15 minutes or until the dough is cooked through. 

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