• Preheat the oven to 200C and set the grill in the oven on.

Egg Yolk Mixture

• Whip egg yolks with 1/3 of sugar until ribbon stage (20-25 minutes).
• Add the vanilla essence, condensed milk and the cognac to this mixture.

Buttercream Mixture

• Cream the butter with a third of the sugar until light and fluffy at medium speed, about 4 minutes.
• Maintaining the speed, add the egg yolk mixture slowly to the cream.

Egg White Mixture

• Whip the egg white until frothy, then add cream of tartar.
• After a minute, add the sugar.
• Beat the egg white mixture to a medium peak at medium speed, on my machine (Kitchenaid liftbowl), it is about 5 minutes.

Combine

• Add the egg white mixture to the cream mixture a third at a time, and folding in carefully.
• Sift the flour and the mixed spices, then fold into the mixture at the same time.
• Set aside on a cool side of the kitchen.
• Line a 9x9 inch square pan.
• Use a ladle, scoop one ladle into the pan. Level this with a spoon or a kueh lapis leveler. This is the the first layer of cake and grill for 2-3 minutes.
• Use a toothpick to poke 8 holes all over the cooked layer of cake.
• Scoop another ladleful, then set it on the grill.
• Keep doing this until the batter is used up.