The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Mexican buns aka coffee cookie buns aka rotiboy buns

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emkay's picture

Mexican buns aka coffee cookie buns aka rotiboy buns

The Chinese like soft and fluffy white breads. The whiter, the better. It might explain why something called Hong Kong flour exists. The HK flour is bleached and low in protein so that the resulting bread is super white and super soft. I don't really mind if my Chinese breads turn out white or not. So I just use what I have on hand which is Central Milling's Artisan Bakers Craft, a 10.5% protein, organic, malted, unbleached flour. The results are definitely more off-white than white. Soft and fluffy is easy. Enrichments such as butter, egg and milk will do the trick. Using a tangzhong aka water roux helps with the softness and keeping quality.


This bun is a purely Asian creation. It doesn't seem to have anything to do with Mexico although buns with a cookie-like topping are reminiscent of conchas. I don't know who invented it first and I have no idea why the Chinese like topping breads with a cookie batter, but it's pure genius. The cookie melds with the bread dough and creates a thin, crispy, cookie-ish layer. Depending on the ingredient ratios in the cookie batter, the layer can be fused with the bread and cannot be peeled off. Or if the cookie batter is stiffer, the baked layer can be peeled or flaked off the bread and eaten separately which is the way I did it as a child when eating boh loh bao aka pineapple buns (which have no pineapple in it at all).

I used instant espresso powder in my cookie topping, but instant coffee powder can be used instead. You can leave out the coffee and have a plain vanilla topping. I used a tangzhong milk loaf for my buns. They turned out super soft, fluffy and shreddable. The topping was crisp on day one, but softened considerably by day two.




I left a few without topping. The topping weighs down the bun a bit so the topped ones spread out instead of up.


The bottom of the bun.


The crumb.



Bakers' percentages for the bun dough

100% flour*, 75% whole milk*, 10% sugar, 12.5% egg, 1% instant dry yeast, 1.5% salt, 10% butter

[* 5% of the total flour was used in the tangzhong. TZ ratio was 1:5 flour to milk.]

Bun dough recipe

To make the tangzhong: In a saucepan whisk 20 g AP flour into 100 g whole milk until it's pretty smooth. Cook over medium heat, whisking constantly, until the mixture reaches 149F/65C. It should be pudding like. Allow the tangzhong to cool before using it in the dough.

380 g AP flour

200 g whole milk, 85-90F

40 sugar

50 g egg

4 g instant dry yeast (SAF red)

6 g salt

40 g unsalted butter, softened

all of the tangzhong

  1. In a KA stand mixer, mix everything except the butter on speed 1 for 3 minutes.

  2. Add the butter and mix on speed 2 until all the butter is incorporated, about 2 -3 minutes.

  3. Bulk ferment at room temp until doubled, about 1 hour.

  4. Scale each bun at 55 grams. (I got 15 buns.)

  5. Proof on sheet pans at room temp for 30-45 minutes.

  6. Pipe cookie topping onto each proofed bun.

  7. Bake buns at 375F for about 15 mins or until golden brown. Best served warm.   

Coffee cookie topping

50g unsalted butter, softened

50g granulated sugar

50g egg, lightly beaten

70g AP flour

1 tsp instant espresso powder

1 tsp water

1/2 tsp pure vanilla extract

  1. Dissolve the espresso powder in the warm water and mix in vanilla extract. Set aside.

  2. Beat the butter and sugar until light and fluffy.

  3. Beat in the egg until well combined.

  4. Beat in the espresso mixture.

  5. Add the flour and mix until just incorporated.

  6. Transfer topping to a pastry bag fitted with a round pastry tip.

  7. Store in the refrigerator until needed. (Can be made 2 day in advance.)

  8. Allow the topping to soften a bit at room temp for about 5 or 10 minutes before piping it onto the proofed buns.

 :) Mary


clazar123's picture

I am always intrigued by the different ways to combine ingredients to make something different.

If you told me that a cookie on top of my bun would taste delicious, I would be very skeptical. But then I would wholeheartedly bite into a piece of coffee cake with a thick layer of buttery streusel and thoroughly enjoy it. I will have to try one of these next time I am at a Mexican (or Chinese) bakery!

Lovely writeup and pictures. Widening my horizons!

emkay's picture

clazar123- I guess a cookie topping on a bun is no more unusual than a lovely streusel on top of a coffee cake. Both are delicious!  

Floydm's picture

Fantastic post.  May I feature it on the homepage for a bit?

It has been years since I've baked them but I have baked melon bread, which uses a similar combination of doughs. I should try it again now that I know about the Tangzhong method.

emkay's picture

Hi Floyd, I think it's similar to melon pan.  I would be so thrilled to be featured. Thanks so much!! -Mary

ExperimentalBaker's picture

Always buy them when I go Malaysia. There's a version with chocolate sauce inside the buns. It's heavenly.

Bookmarked and will try yours soon.

emkay's picture

A chocolate sauce inside sound so decadent. I might have to try making that. Thanks!

dabrownman's picture

Don't know if i should put ice cream and chocolate sauce on it or butter and jam.  Bet it is good either way. these are way better than conchas.   Well done and

Happy baking

emkay's picture

Cookie bun does sound strange, doesn't it? :) And I like these more than conchas too. Thanks dab!

CAphyl's picture

Mary:  Thanks for sharing; the pics are fab.  Would love one of those buns right now.  Congratulations!  Best,  Phyllis

emkay's picture

Hi Phyllis, Thanks for the kind words. :) Mary

isand66's picture

I thought I commented on this a few days ago, but alas the gremlins must have struck again.

These look awesome Mary.

Thanks for sharing with us and congrats on the front page.


emkay's picture

Hi Ian, No worries! Those gremlins are a pesky bunch. :) Mary

pantone_000's picture

Hi emkay! I too have been practicing Roti buns for some time now (but with a recipe from youtube). I have tried both the direct method and using a tangzhong. I noticed the softer texture with the tangzhong roti but it is not as noticeable with my family. Emkay, what is the diameter of your finished buns? Mine were around 2inches after filling was put inside and rolled to its final shape. I timed the second rise at around 40-45mins too. And then baked them 20min at a low 300F (I use a brick oven) and the final size is only at 3in diameter, thus the crumb was denser than what I expected it to be. I am afraid to let it rise for too long (at room temp, no option for retarding) for it may not have the strength for its oven spring. My tasters liked that it was a little bit dense though as it was more tummy-filling than if I had let it rise too much. Here they are:

After 2nd rise, piped the crust batter before it goes to the oven.


emkay's picture

Hi pantone_000, I scaled my bun dough at 55 grams each, but I don't have a diameter of the pre-proofed dough balls. Mine were unfilled. Each finished baked bun was 3.3 inches/ 8.5 cm in diameter.  300F for baking seems low to me, but I don't know how a brick oven compares to a domestic home gas oven.

I've never had a problem with tangzhong breads turning out dense which is one of the reasons why I like it. I have had dense enriched buns made from sponge starter doughs, but mainly because I underproofed either at the sponge step, or during the final shape proof. 

Hope this helps.



pantone_000's picture

Thanks Mary. I scale mine at 45g and then the filling (breadcrumbs, sugar, buter) at more or less 10g. I wonder how I can make those tangzhong Japanese breads that are as light as cotton without using any dough conditioner/softener. TZ method is good for homemade breads, but I also wonder if that would be practical for bulk bakes (eg. 4-5 or more batches).

emkay's picture

Although I've never made 3, 4 or 5 kg of dough with tangzhong added, there's no reason why it shouldn't work. The TZ can be made ahead of time and used just like any pate fermentee (old dough). 

Kaipea's picture

Those look beautiful! I have to try this, thank you~

Kaipea's picture

I did it! They filled the room with sweet coffee aroma. Mine didn't came out pretty, (might be because I didn't use a pastry tip?), but they were yummy. :D I'll try again soon!

emkay's picture

Hi Kaipea, I think your buns look great. The pastry bag and tip helps, but the topping melts and spreads in the oven so you can't really tell with the final product. Great job!!

Atihcnoc's picture

I love this bread, I grow up eating "Conchas" at the tea time (merienda), the first time I ate "Rotiby"  I was living in Indonesia, imediatelly remind me to my beloved  "Conchas" I was so intrigued that I investigate and found the explanation in the creator of "Rotiboy" ( was born in 1998 and is the generic name of the Mexican bun recipe it was based on. So Rotiboy is based in the "Conchas" bun recipe. If you investigate you will find that "Conchas"  has a lot of toppings. I'm 59 yrs old, and my grand,grandmother grow up eating Conchas as well.  Hope that answer this:  This bun is a purely Asian creation. It doesn't seem to have anything to do with Mexico although buns with a cookie-like topping are reminiscent of conchas. I don't know who invented it first......The answer is Mexico invented first, the bun is not an Asian creation.   But it is a good one and it is... delicious! Thank you for sharing your recipe.