Also known as a magic custard cake. A simple mixture that resembles a thick-ish running mixture which magically transform during baking – the bottom layer becomes like a thick baked custard with a spongy cake on top. The original recipe used orange marmalade (hence the name), however, I used whatever jam I had opened at the time. If you want a vanilla custard cake, simply omit the jam/marmalade and add 1 teaspoon vanilla extract (and 1 teaspoon of vanilla paste if you have it) when beating the egg yolks with the sugar.
1/2 cup marmalade or jam
125g unsalted butter
4 eggs, separated
1/2 cup caster sugar
1 cup plain flour
500 ml milk
1 teaspoon white vinegar
Preheat your oven to 160ºC. Line either a 20cm square cake tin or a slice tin (18cm by 28cm) with baking paper.
Combine the marmalade or jam and butter in a small saucepan and heat until the butter is just melted. Set aside to cool slightly.
In a mixing bowl, beat the egg yolks and sugar until pale and fluffy. Add a tablespoon of cold water and the melted butter mixture and whisk to combine. Continue to beat slowly, add the flour, than add the milk slowly a little at a time until the mixture is smooth.
Separately whip the egg whites to firm perks and add the vinegar, whisking to combine. Fold half the egg whites into the batter mixture until combined, then fold in the remaining egg white. Pour the mixture into the prepared tin and bake for 45 minutes (the mixture might go right up to the top of the cake tin, it will be fine), or until the top is brown and the edges are well set. The cake should still be a bit wobbly in the centre.
Cool to room temperature in the tin, then chill in the fridge for 2 hours or overnight. Remove, slice and dust with icing sugar to serve.