The Ultimate Pandan Honeycomb Cake (Bánh Bò Nướng)

If you step into a Vietnamese bakery or gather around a family dessert table, you’ll realize pretty quickly that Bánh Bò Nướng — Vietnamese Honeycomb Cake isn’t just your ordinary sponge cake. From its striking emerald green hue to its mesmerizing, porous interior, this dessert stands completely in a league of its own. Today, I want to show you how to master this stunning, aromatic classic right in your air fryer with a foolproof technique.

What makes a truly legendary Bánh Bò Nướng isn’t just the sweet fragrance of coconut—it’s achieving that perfect, delicate balance between a crisp, golden outer crust and a springy, deeply chewy interior filled with vertical honeycomb tunnels.

Memories of Home: A Gathering Staple

Growing up, I actually didn’t have a lot of memories of eating this on the streets of Vietnam when I was young. Instead, my memories of this cake are tied to the laughter and noise of family parties. It seemed like every time we gathered, a bright green cake would appear on the table. Over time, it became a frequent, comforting staple in my life for a beautiful reason: it happens to be one of my mother-in-law’s absolute favorite things to bake. Watching her bring this finicky cake to life made me appreciate just how much love is baked into every single honeycomb strand. I shied away from baking this cake for many years because of the number of times I’ve failed at it, but this fool-proof air-fryer recipe has me completely hooked!

Things to Know Before You Start

• The Single-Pack Baking Powder Secret: Bánh Bò Nướng relies on an aggressive chemical reaction to shoot carbon dioxide bubbles straight up from the bottom through the heavy tapioca batter. Never use baking powder from a large tin that has been sitting in your pantry; once exposed to air and humidity, it loses its punch. You must use fresh, individually packaged baking powder to guarantee the maximum chemical potency needed for that dramatic rise.
• The Aluminum Advantage: Drop the silicone, ceramic, or glass bakeware. Aluminum is a phenomenal heat conductor that warms up instantly. To get those beautiful vertical tunnels, the batter needs an immediate, aggressive shock of high heat from the walls of the pan to force the air bubbles rapidly upward before the starch sets.
• The Pandan Consistency Rule: While fresh pandan leaves are wonderful, they inject a highly unpredictable amount of water into your recipe every time you blend and strain them. To keep your liquid content perfectly consistent and controlled, rely on a high-quality store-bought pandan extract. It delivers a reliable, vibrant green color and punchy aroma without ruining your starch ratios.

Ingredients and Substitutions

(Note: Full exact measurements can be found in the printable recipe card below!)

• Tapioca Starch & All-Purpose Flour: High-quality tapioca starch is mandatory to give the cake its signature springy, chewy texture, while a tiny touch of all-purpose flour gives the honeycomb structure stability so it doesn’t collapse.
• Coconut Cream: Rich, full-fat coconut cream gives the cake its luxurious, moist crumb and decadent mouthfeel.
• Pandan & Vanilla Extract: The ultimate aromatic duo for that authentic, sweet, and botanical fragrance.
• Eggs: But here is the insider trick—we remove a portion of the whites from one of the eggs. Cutting back slightly on the egg whites reduces excess moisture and sulfur, ensuring your cake has the perfect chewy texture without being overly wet or smelling too “eggy.”
• Double-Acting Baking Powder & Melted Butter: Essential for that massive upward rise and a glossy finish.

Step-by-Step Instructions

1. Preheat the Air Fryer: Place your aluminum cake pan inside the air fryer and preheat it to 300°F for 10 minutes. The pan must be screamingly hot before the batter touches it.
2. Mix in One Direction: In a large bowl, combine your tapioca starch, all-purpose flour, sugar, salt, coconut cream, vanilla extract, pandan extract, and the adjusted eggs. Using a rice paddle or silicone spatula, mix the ingredients smoothly in ONE direction only. Keeping your motion strictly unidirectional prevents you from whipping excess air or trapped oxygen into the eggs, which would ruin the uniform vertical tunnels.
3. First Strain: Pour the smooth batter through a fine-mesh sieve strainer to catch any stubborn, unblended starch lumps.
4. Activate the Leavening: Add your double-acting baking powder to the strained batter, stirring gently to incorporate.
5. Second Strain: Run the batter through the sieve strainer a second time to ensure the baking powder is completely distributed and flawless.
6. Enrich with Butter: Pour in your melted butter and mix thoroughly until the batter is completely uniform and glossy.
7. The Sizzle Pour: Carefully remove your hot pan from the air fryer and coat it lightly with a thin layer of oil. Pour the green batter through a colander directly into the hot, oiled pan. Passing it through the holes of a colander splits the batter, helping to naturally guide those beautiful vertical honeycomb strands as it hits the sizzling hot pan.
8. Seal It Up: Securely cover the top of the pan with a sheet of aluminum foil to trap the moisture and ensure an even, uniform rise.
9. The Air Fryer Bake: Bake in the air fryer at 300°F for 35 minutes. Once the timer goes off, carefully remove the foil and bake for an additional 3 to 4 minutes at 335°F to give the top of the cake a stunning, golden-brown caramelized finish.

Tips for Success and Mistakes to Avoid

• The Cooling Mandate: Never cut into this cake while it is hot! You absolutely need to let it cool completely to room temperature before serving. If you cut it early, the internal structure hasn’t fully set, which leaves the cake with an unappetizing, overly eggy taste and a collapsed texture.
• Do Not Over-Whisk: Remember, this isn’t a western sponge cake. Treat the batter gently and avoid vigorous whisking or beating, which introduces massive pockets of random air instead of those beautiful, tight, parallel honeycomb strands.

How to Serve

Once the cake has cooled completely and the flavors have settled, slice it into thick wedges or diamonds using a sharp, lightly oiled knife. Serve it alongside a hot cup of tea or jasmine green tea. Each slice should clearly show off those gorgeous, vertical “honeycomb” tunnels from top to bottom.

Make-Ahead, Storage and Reheating Tips

• Storage: Store any leftover slices in an airtight container at room temperature for up to 2 days. If you need to keep it longer, store it in the fridge for up to 5 days, but note that the starch will firm up when cold.
• Reheating: To bring back that glorious, soft, chewy texture from the fridge, simply flash-microwave a slice for 10 to 15 seconds, or pop it back into your air fryer at 300°F for 2 minutes to crisp up the edges again!

FAQs

Why did my cake turn out flat without any honeycomb strands? This usually happens if your baking powder was old or if your aluminum pan wasn’t preheated until it was screaming hot. The batter needs that immediate shock of heat to force the bubbles upward instantly.

Can I use a silicone mold instead of aluminum in my air fryer? Avoid silicone molds for this specific recipe. Silicone acts as an insulator and heats up too slowly, which will cause the batter to bake flat and dense rather than shooting upward to create the iconic tunnels.

Why is Bánh Bò Nướng green? The color comes from pandan, an aromatic leaf used throughout Southeast Asian baking. It’s responsible for both the cake’s signature emerald hue and its sweet, slightly grassy fragrance — not food coloring.

Pro Tip: If you like this recipe, try my Bánh Flan Air Fryer recipe for another foolproof Vietnamese dessert made with the same water-bath/air-fryer approach.