Preheat the oven to 350 degrees F (180 degrees C), grease a large rimmed cookie sheet, line with baking paper, then grease the paper.
Whisk the egg whites, gradually adding in half the sugar until you get stiff peaks.
In a separate bowl, whisk the egg yolks and rest of the sugar until thick and pale.
Add the egg whites and rest of the cake ingredients to the bowl with the egg yolks and fold together gently until fully combined.
Pour into the lined baking sheet, spread out evenly and bake for 15 minutes.