Mocha Ogura Cake

Original recipe by Kitchen Tigress 

Ingredients: 
310g egg white
1/2 tsp cream of tartar
140g caster sugar

125g egg yolk
100g egg white
80g cooking oil -- I used rice bran
40g cocoa powder
140g brewed coffee -- see notes
110g plain flour
1/2 tsp salt

Line a 25cm round cake tin. If you have a pan that is at least 8cm tall, you can choose not to line the sides. (see notes)

Heat the oil until smoking. Stir it slowly into the cocoa powder until it is smooth. I recommend adding just enough oil to form a thick paste with the cocoa powder, smoothing it out, and then stir in the rest of the oil.

Put the kettle to boil. Place a roasting pan or similar at the bottom of the oven, and preheat it to 170C.

Whip 310g of egg whites until foamy and add the cream of tartar. Once the cream of tartar is dissolves, add the sugar in slowly. Whip until stiff peaks.

Whip the remaining egg white and yolk until foamy, then tip in the cocoa mixture. Whip until thick. Keep whipping while slowly pouring in the coffee.

Gradually sift the flour into the bowl. Add the salt last.

Fold the whipped egg whites into the cocoa mixture in thirds. Make sure there are no lumps of egg white and no white streaks.

Pour the mixture into the prepared cake pan at a height.

Pour the hot water into the pan -- 1cm of water should be enough -- and put the cake in. Bake at 170C for 30 minutes, and then turn it down to 130C until it's no longer jiggly in the middle and the top bounces back when gently pressed.

Let rest in the pan for 10 minutes or so, before turning it out onto a plate. Peel off the paper on the sides, if used, then let cool completely before slicing.

Pan Size: 
I used a 25cm round tin that is 8cm high, but the cake rose to 12cm or so in a mushroom shape before it sunk. So you can probably use a larger tin or half the recipe for a 20cm square tin (would still need to have high sides).

Tasting Notes: 
Lovely. Soft, fluffy and moist mocha sponge.
Try to wait until it's completely cool to slice so that it does not wet down. I was greedy and unable to do this.

Coffee Notes: 
I used some sous vide brew made with a boost of vanilla powder, but I will try using a stronger filter brew the next time I make this.
You can substitute water mixed with instant espresso powder, but I find that it does not taste as good.

Future Notes: 
I plan to try a chai version for my man soon, as well as a green tea version.