Honey Castella (Kasutera) Cake

The traditional mould for baking Castella cake is a bottomless wooden box frame. You could buy one, make one, or improvise with my method. I put the pan holding the batter in a bigger pan, and there's corrugated cardboard tucked in the space between the two pans. To prevent the cardboard from catching fire in the oven and then burning down the house, I wrap it in foil.

Where to get a Castella wooden mould? You could buy one, make one, or improvise with my method. I put the pan holding the batter in a bigger pan, and there's corrugated cardboard tucked in the space between the two pans. To prevent the cardboard from catching fire in the oven and then burning down the house, I wrap it in foil.

Once you get the mould sorted, you need to pick a recipe. Which one should you go for? Mine, of course!

My Castella cake is soft and moist freshly baked. Yup, you don't have to wrap it in plastic and wait a day before eating it. Nope, I don't cheat by adding oil or that awful stuff, ovalette (aka SP). Neither do I sneak  plain or cake flour into the cake. I use only only bread flour, as I'm supposed to, but the cake eats like it's made with cake flour.

How do I make a stellar Castella cake?

I start by beating 85 g egg whites with 60 g sugar till firm peak stage, i.e. between soft and stiff. Too much egg white would make the top of the cake wrinkled after cooling down. Too little would result in a dense crumb.  Underwhisking would result in the cake collapsing. Whisking too quickly or too much would make the crumb coarse and holey.

Once the meringue is firm yet smooth and creamy, I add 60 g egg yolks. Most home recipes use an equal number of whites and yolks but I use more yolks than whites. Why? To help make the cake soft and moist, and the top flat and wrinkle-free. The yolks must be added one at a time or the meringue would deflate. And the whisking must be done at low speed, to help remove big air bubbles in the meringue.

There is, of course, honey in honey Castella cake. How much? Just 20 g, enough to flavour the cake but not make it sticky. Honey is whisked into the batter after the egg yolks.

After the honey comes 60 g bread flour. The less flour there is, the softer the cake is. Unfortunately, too little flour would result in a coarse crumb and a crumpled top, two definite no-no's for Castella cake. Too much flour would make the cake dense and hard, another hallmark of Castella cake failure. Getting a tight yet soft crumb requires great balance.

The last thing added to the batter is 20 g milk. As I fold it into the other ingredients, I bang the mixing bowl against the worktop from time to time to help remove big air bubbles.

Halfway through the mixing, I let the batter rest for a few moments. Perhaps thinking the coast is clear, some unsuspecting air bubbles rise to the surface. And that's when I nap 'em. Bang! Bang! I'm so sneaky, yah?

Transferring the batter into the cake pan gives me another chance to catch those nasty bubbles. I pour slowly, from a height, so that some of the big bubbles burst as they flow out of the bowl. What do I do before the pan goes in the oven? Yup, bang bang! It's zero tolerance for Castella cake's #1 enemy.

Which shelf in the oven do I use? Bottom, so that the bottom of the cake browns as nicely as the top.

After the cake is done baking, I drop the pan from a height to stop it from shrinking excessively as it cools down. This is the neatest trick I've ever come across in cake making!

Here's another good trick: invert the pan and let it rest on a wood chopping board for a few moments. This helps keep the top of the cake flat and smooth.

Just before serving, trim the edges of the cake. The cuts must be neat and clean or you've failed even if the cake is perfect in every other way. I hope you're the obsessive-compulsive type?

HONEY CASTELLA CAKE (蜂蜜蛋糕) (Recipe for one 20 x 12 x 5 cm cake) 85 g egg whites 60 g castor sugar 60 g egg yolks 20 g honey 60 g bread flour 20 g full-fat milk Cut 5 mm thick corrugated cardboard to fit 4 sides of 23 x 15 cm cake pan. Wrap tightly in aluminium foil, shiny side facing out. Line 4 sides of cake pan with cardboard. Cut parchment paper to fit bottom of 20 x 12 x 5 cm cake pan. Grease lightly with vegetable oil. Place paper in cake pan, oiled side up. Preheat oven to 160°C. Whisk egg whites till bubbles are very small. Gradually add castor sugar whilst still whisking. Continue to whisk till firm (not stiff) peak stage, reducing speed towards the end to remove big air bubbles and prevent overwhisking. Add yolks to whisked egg white in 4 batches. Whisk on low speed till evenly mixed after each addition. Add honey. Repeat whisking as before. Sift half of bread flour into batter. Mix with whisk till almost even. Sift remaining flour. Mix till just even. Drizzle milk around bowl. Whisk, skimming just top part of batter, till you don't see any milk. Scrape down and fold with spatula, banging bowl against worktop from time to time, till everything is just evenly mixed. Let batter rest 10 seconds or so midway, then bang bowl against worktop. Pour batter into lined cake pan, slowly and from about 30 cm high so that air bubbles burst as they flow out of bowl. Tap pan against worktop 3-4 times. Place in bigger cake pan prepared earlier. Bake in bottom of oven till cake is brown and makes a soft squishing sound when pressed lightly, about 35 minutes. (If squishing is loud, cake is still too wet. If there's no sound at all, cake is overbaked and too dry.) Remove pans from oven. Remove cardboard and outer pan. Drop smaller cake pan from about 30 cm high, 2-3 times. Wait a few moments till top of cake starts to wrinkle slightly. Invert pan onto wooden chopping board. Wait till top of cake is flat and smooth, about 30 seconds. Re-invert pan. Leave on wire rack till cool. Unmould, trim edges, cut and serve. Cake is best eaten on day it's made, especially if it's cut. If serving the next day, or if cake is overbaked, wrap in plastic whilst still warm and unmoulded, till serving time.