The Ultimate Guide to Banh Bo Nuong (2024)

3 Tips to a Failproof Honeycomb Cake

One of my favorite sweets from childhood is Banh Bo Nuong, otherwise known as Honeycomb Cake. It’s a sponge cake with striations (air tubes) running up and down the cake, giving the look of honeycombs when looking at the cross section. Banh Bo are a wide variety of sweet, chewy cakes common in Vietnam, often made with tapioca starch, rice flour, and/or coconut milk; this one is baked. The cake is generically a creamy white or yellowish color, but we get this bright green color from Pandan flavoring. Pandan is basically the Vanilla of Asian baking flavors, and one of my absolute favorites to work with. I love it, my family loves it, and it’s one of my go-to recipes I always bake at home.

I only started making my own banh bo nuong nearly two years ago, but the initial search for a working recipe showed that it was one of those things that a lot of people get wrong and have to experiment with for a long time. To me, that turns people away from recipes. Priming with the thought that the recipe fails easily doesn’t make me want to try it. But this one works, and I say with confidence that you will not fail. I didn’t have any trouble in making this cake and I’ve made it a dozen times since the beginning of the year.

When I search for recipes, I look through several to get an overall understanding for the general procedure and ingredient ratios. I rarely ever try a recipe after looking at only one, especially with everything on the world wide web. I prefer ones done on blogs, with commentary and proof that their recipe worked, and luckily, I stumbled upon the350degreeoven.com’s recipe!

One of the main things that turned me away from the other recipes was the need to buy a certain kind of baking powder, and while I did search for it at two Asian grocery stores, I couldn’t find it, so I settled for this recipe where we can make our own. I’ve adapted my recipe from hers, but I added my explanations, a few ingredient amount and procedural changes, and little tips to make a failproof honeycomb cake. It’s a delicious cake that deserves to be made and eaten at home. This is fairly lengthy, but be sure to read through the tips at least once and keep them at the back of your mind so you know how and why the recipe works!

Let’s get baking! Onto the recipe!

There are bits of culinary chemistry lessons thrown in here. Chemistry is the basis of all culinary reactions, and I love learning more about it so that I can put together good, working recipes. It helps explain how things work when mixed together, and here I will use it to explain my top 3 tips for making Banh Bo Nuong.

There isn’t a lot of equipment or ingredients involved, and doesn’t take long to put together. You won’t need an electric mixer or anything of the sort. We’re going simple and quick.

Equipment:

Scale, sieve, whisk, rubber spatula (heat proof silicon), bowl scraper (optional), microwavable bowl/cup or pot, angel food cake pan OR 9″ cake pan, 2 mixing bowls, 1 metal bowl

Here are the ingredients! Not too many, but they work together to form our amazing honeycomb patterned cake. They will be listed in the recipe below.

Step 1. Combine coconut milk, sugar, and salt in a heatproof bowl. Heat until sugar dissolves. About 2 minutes, stir half way through. (Alternatively, heat on the stove until sugar dissolves.)

I just do this in my glass measuring cup and microwave to minimize on dishes and time.

*I have been using coconut cream to make this, but last time I looked at another recipe and it simply said coconut milk, so I tried it with coconut milk during this trial for the recipe pictures and it worked perfectly fine! I shook the coconut milk can before measuring, so no need to scoop out just the top creamy layer out. Coconut cream is generally more difficult to get, so it is great to know that we can use either one. Just make sure to use real coconut milk – usually in cans – and not the watered down coconut milk for drinking. As for differences, the coconut milk created a slightly softer, more translucent cake and richness was not drastically cut, so go for whichever is more convenient to you.

Step 2. Pour warm coconut mixture into a metal bowl. Place in refrigerator to cool for an hour.

*Moving the mixture into a metal bowl allows it to cool faster than in microwavable glass or plastic. The goal is not to make the mix cold, but rather room temperature so that it doesn’t cook the eggs when we add it in later.

Step 3. Add pandan paste to the room temperature coconut milk and stir to combine.

I use Koepoe-Koepoe brand pandan paste. Since paste is denser in color and flavor, you can use more to your liking if you have pandon extract or other products. These can be found in most Asian grocery stores in a variety of flavors. I finally got one of the bigger bottles since I like to use it so much!

Step 4. Preheat oven to 375F. Spray the bottom of the cake pan. Place cake pan in heating oven.

It’s better to have the oven preheating before starting to mix everything together. This is a fairly quick cake to mix and the batter is time sensitive so you will want to make sure the oven is up to temperature when the batter is ready.

Only spray the bottom of the cake pan. Like most other sponge cakes, the batter needs something to cling to when it is rising so that it can stay risen and not fall out when inverted to cool. For the same reason, do not use nonstick pans. I prefer aluminum pans where the base is detachable for easier removal of the cake, but it is fine if the bottom doesn’t come off, you’ll just have to be more delicate when removing the cake. Do not use parchment, it will rise and float in the middle of the batter.

Step 5. Place the eggs in a bowl and using a whisk, break the yolks lightly. Slowly stir using the whisk until the eggs are mostly smooth and combined. *Refer to TIP NO. 1

TIP NO. 1 Mix slow and gentle

One of the keys to the honeycomb cake is to avoid incorporating air. I believe the reasoning is that we want a dense batter – the single acting baking powder we add will do its magic to create the striations running through the cake. If we were to whip it up like other sponge cakes, the batter would be too thin and unstable to hold the air tubes, and also collapse while cooling after rising high in the oven.

To do this, we mix it slow and gentle, avoiding quick motions that would whip the batter up.

I start by poking at the eggs with the whisk. Lightly tap down on the yolks to break it apart. Don’t smash down on it and ruin your whisk. Then slowly stir in circles and side to side. I also lift my whisk up sideways a bit to have the egg whites run through. Avoid moving your wrist like you would for whipping cream and instead move your whole arm so that the eggs gently break apart.

Some recipes call for using scissors to cut at the yolks, or stirring in only one direction, and while those might work, it isn’t necessary if you just stir gently.

There will be some bigger parts left, but we’ll take care of that later.

Step 6. Add coconut mixture into the eggs and gently stir to combine.

Step 7. Sift the tapioca starch. (Sorry, no picture for this, but you can do this step anytime before the next one.)

*I use the same sieve to sift the starch and the eggs, so remember to sift the starch first so that you won’t have to wash and dry the sieve again.

Step 8. Sieve the egg mixture into another bowl. Larger bits may stay behind in the sieve. Pass them through by slowly pressing on them back and forth with the flat side of the rubber spatula until it all falls through. (Alternatively use the bowl scraper if you’d like, or when doing larger batches.) *Refer to TIP NO. 2

TIP NO. 2 Sieve the mixture… several times

To thoroughly mix the batter without incorporating air, we sieve it to get rid of lumps and disperse all the ingredients. I usually sieve a minimum of 4 times. Once with the eggs, twice with the starch added, and once or twice when the baking powder is added. Give it a stir between each sieving and then pour it through the sieve to ensure a smooth batter.

*You may notice that a lot of it gathers and sticks to the bottom of the sieve. Simply use the edge side of your rubber spatula to scrape against the bottom of the sieve to release the batter for quicker passing through.

Step 9. Add the tapioca starch to the eggs. Mix gently with whisk. There will still be many lumps.

Step 10. Pass the mixture through the sieve, slowly pressing back and forth on the lumps with the rubber spatula.

*Sometimes you may need to add some of the liquid back into the sieve to mix with the lumps to break them up easier.

Step 11. Give the mix a stir, then pass it through the sieve again.

TIP NO. 3 Add baking powder in last

The single acting baking powder is the last key to a successful Banh Bo Nuong. It is different from the usual baking powder you buy in containers; that is double acting baking powder.

The difference is that single acting baking powder only causes the leavening once it gets in contact to moisture, whereas the double acting baking powder leavens both with moisture contact, and again with heat contact in the oven. This makes a huge difference in our honeycomb cake – we have to act quickly to put the batter in the oven once the baking powder is added so that it doesn’t all fizz out before it gets baked into the signature striations of the honeycomb. Sieving the starch lumps through takes a while, that’s why I add the baking powder in last, after the other dry ingredients are added in.

Single acting baking powder is more difficult to find, usually Alsa brand, which are sold as small pink packets in some Asian grocery stores and sometimes inaccessible. However, we can easily make our own.

Single acting baking powder is simply a mix of cream of tartar and baking soda. It is a 2:1 ratio of cream of tartar to baking soda by volume. Weighed out for this recipe, it is 5 grams cream of tartar and 4 grams baking soda.

DIY Single Acting Baking Powder

5g cream of tartar and 4g baking soda (for this recipe)

Step 12. Working quickly but gently, add the single acting baking powder. Stir lightly with the whisk, and pour it through the sieve. *Refer to TIP NO. 3

Step 13. Pull the hot cake pan from the oven. Give the batter one last stir (you will see it starting to foam on top), and pour or sieve it into the cake pan. (You will only have one cake pan if you follow the recipe amounts exactly)

*The foam (lighter part) rising to the top of the batter shows that your single acting baking powder is already working. We want to get it into the oven as quickly as possible once the baking powder is added. You can sieve the mix into the cake pan, but do not fuss and take too much time.

Step 14. Bake at 375F for 10 minutes. Without opening the oven, turn the oven down to 320F and continue baking for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Meanwhile, you can clean your dishes! There really isn’t much which is one of my favorite things about how simple this recipe is.

*When opening the oven, make sure to open it just a crack and wait a few moments, before fully opening the oven. This is especially important for sponge cakes or cakes that are sensitive, that rise a lot and deflate after baking. Doing so not only avoids you a heat wave and steam facial, but the oven temperature won’t drop rapidly with the sudden inflow of air from temperature difference and flood the area with steam.

Ta-dah! Your Banh Bo Nuong after baking! You did it! And the heavenly aroma of pandan and the finished cake fills the house, but you have to wait!

Step 15. Invert the cake pan onto a cooling rack and cool for 90 minutes before removing from pan.

Many sponge cakes are cooled this way to ensure it doesn’t collapse on itself and deflate or get a dense bottom. Sadly, you do have to wait before tasting your precious honeycomb cake.

Step 16. Remove the cake from the pan by gently pressing around the edge with the pad of your fingers, and then pressing it off from the bottom. (continue gently prying at the edges if the bottom of your cake pan doesn’t come off. Banging the side of the pan on a surface may help loosen it.)

It’s finally out!

Step 17. Cut, serve, and enjoy!

You can warm it back up by putting it in the microwave for a few seconds.

Full Recipe:

If you make this recipe and share it, be sure to tag me on Instagram @cherrycindyy and hashtag with #sweetdreambakes. I’d love to see your bakes!

This recipe has not failed me yet, so let me know if you have any questions or troubles and I will do my best to solve it with you!

Good luck and happy baking!

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This is my first recipe posting!! Thank you for reading and I hope you enjoy baking and eating Banh Bo Nuong as much as I do.

I will try to add a printable/savable version of the recipe, but it may take a month or so since I’m going on vacation in a few days. I was in a bit of a rush but I wanted to get this out as soon as possible. I will update with all your suggestions once I get back. *I have tried doing the printable one but I can’t get it right since it’s only made with shortcode and I don’t understand that completely, so sorry, but there is a simpler version at the end of the post.

I don’t like working with measuring cups and spoons, and I highly recommend getting a scale so that the recipe is as accurate as possible, less messy to work with, and you’ll have less dishes to wash. If you must use them though, you can convert the recipe by looking up each ingredient’s weight to volume measure, or reference the original recipe link – but I have changed some amounts so it may not come out the same way.

Sorry for the non-glamorous pictures! I just wanted to clearly show how the recipe works and the simple but sometimes messy process of baking.

THANK YOU! 🙂