I’m a huge fan of chocolate and cake, so when I discovered this recipe, I knew I had to share it. It’s inspired by the famous Original Cake bakery in Johor Bahru, Malaysia. After watching how they bake their signature cakes in-store, I realized their method is a bit different from most Castella recipes you find online.

In this post, we’re diving into the secrets of this incredibly light and decadent chocolate cake. This recipe is perfect for one 8-inch cake or two 6-inch cakes. Feel free to adjust the amounts to your needs!

A Quick Note: I’ve made a few tweaks to the original shop recipe based on what I had in my pantry. These are all common staples, but I’ll mention what the bakery uses if you want to aim for that 100% authentic flavor.

Instructions

Step 1. Prep the Eggs

Separate the egg yolks from the whites. Place the whites immediately into the refrigerator. Be careful not to get any yolk in the whites, or they won’t whip up properly!

Step 2. Prep the Chocolate

Chop your chocolate block into small pieces or crumbles. I prefer 70% cocoa for a rich, balanced sweetness, but 66% works great if you like it a bit sweeter.

Ensure the crumbles aren’t too large, or they will sink to the bottom during baking.

Step 3. Heat the Oil & Cocoa powder

In a small saucepan, combine the corn oil and about 1 tablespoon of your chocolate crumbles (roughly 15g).

Heat the oil mixture to 175°F. Once it reaches temperature, sift in the cocoa powder.

Step 4. Add milk & cake flour

Add the milk continue heat the mixture until it reaches 175°F again, then turn off the burner. Whisk the cake flour into the warm mixture until well combined.

Step 5. Form the Paste

Let the mixture cool slightly (so you don’t scramble the eggs!), then whisk in the egg yolks until the batter is smooth. If the batter feels too dry, add a splash of milk; if it’s too runny, add a pinch more flour.

Step 6. Whip the Meringue  

Take the egg whites out of the fridge and add the lemon juice. Whip the whites until soft peaks form. Gradually add the sugar in three stages, whipping until you have a glossy meringue.

Step 7. Combine

Gently fold 1/3 of the whipped egg whites into the chocolate mixture to lighten it up.

Pour the chocolate mixture into the remaining egg whites and fold gently until no streaks remain.

Step 8. Prep the bake

Preheat your oven to 265°F and prep your cake pan.

Line both the bottom and the sides of your cake pan with parchment paper. The paper should be taller than the pan because the cake will rise significantly during baking.

Step 9. Pour the batter into the pan

Pour the batter into the pan until it’s half full. Evenly sprinkle your chocolate crumbles over the surface.

Pour the remaining batter into the pan to cover the chocolate layer.

Step 10. Bake 

Bake at 265°F for 45 minutes.

Lower the temperature to 250°F and bake for another 25 minutes.

Finally, increase the heat back to 265°F for a final 10–15 minutes.

Step 11. Cooling 

Remove the cake from the pan and peel off the parchment paper immediately. This allows the steam to escape and prevents the cake from getting soggy.

You can enjoy this cake fresh and hot out of the oven for a “molten” chocolate filling, or let it cool in the fridge. It is incredibly soft and has a very rich chocolate flavor. Because the chocolate is so prominent, it covers the “eggy” taste often found in sponge cakes, making it a perfect choice for anyone who wants a light texture without the egg-forward flavor.