Marble cake...

Ingredients
200g butter
4 eggs
200g sugar
4g salt
200g flour
2 teaspoon vanilla flavor
30g cocoa powder

Preparation
Step1
Preheat the oven at 180ºC.

Step2
Melt the butter in a sauce pan. Once melt the butter, remove from heat.

Step3
Separate the yolks from the whites.

Step4
Add sugar and salt in the yolks and mix them with a wooden spoon.

Step5 
Add alternately flour and melted butter and whisk.

Step6
Whisk egg whites into meringue. Add vanilla flavor.

Step7
Mix meringue with egg yolks mixture.

Step8
Separate the mixture in half. Add the cocoa powder in one half of mixture.

Step9
Put alternately from the two mixtures in a buttered baking pan.

Step10
Bake in the oven at 180ºC for 50-60 minutes.