When we were in Japan last year, I kept seeing these massive, fluffy Castella cakes being sold. They’re a sponge cake, with origins from 16th century Portugal, but sold everywhere in Japan.

I was tempted to stop at Fan Pai Pai in Shibuya, Tokyo as I saw they had a chocolate special. I’m always going to be interested in a chocolate cake.

I was obsessed with this cake. It was so large that it took me about three days to eat it, but it was delicious. The sponge was bouncy and fluffy and it contained little chocolate chips to provide texture and flavour. They had mostly sunk to the bottom of the cake due to the lightness of the sponge, but that meant that there was a lovely chocolatey layer at the bottom.

So when I got home, I immediately set out to look for a recipe to try and recreate this myself.

This came out really well; not identical to the cake we had in Japan but not too far off! The texture was light and spongy and it was full of chocolate flavour.

I served it with homemade matcha ice cream, but is good with a cup of tea as well.

Recipe from Better Home Base. Serves 8.

• 100 g cake flour
• 95 g vegetable oil
• 18 g cocoa powder
• 25 g dark chocolate
• 100 g milk
• 8 eggs
• 95 g granulated sugar
• 8 g vanilla extract
• 8 g lemon juice

Preheat your oven to 320°F (160°C). Seperate the eggs and keep the egg white bowl in the fridge.

Heat the vegetable oil to 158°F (70°C). Transfer the heated oil to a clean bowl, add in cocoa powder and flour and mix well.

Add in melted dark chocolate and milk and mix well. Add in egg yolks and mix well. Set aside

Add lemon juice, granulated sugar and vanilla extract into the egg white, use a hand mixer to beat until it forms soft peaks

Take a scoop of whipped egg white to fold into the batter until just combined. Pour all the whipped egg white into the batter. Gently fold the whipped egg white into the batter until just combined.

Line the square springform pan (24x24x8cm) with parchment paper and pour all the batter into the pan Smooth the surface. Give it a few taps (optional)

Wrap the baking pan bottom with tinfoil to avoid water getting into the cake during water-bath baking. Pour some room temp water (about 1cm high) into the baking sheet and place the springform cake pan into the baking sheet. Send into the oven to bake for 65 minutes

Once the cake is fully cooked, take it out of the oven. Take the cake out of the springform pan and let it cool down on the cooking rack or the cake may get too moist.