Mix eggs well with a pinch of salt.
Add the sugar and mix until the eggs have doubled in volume and turned white.
Pour oil little by little, milk and continue mixing.
Separately mix the flour with the baking powder and add it to the egg composition. Mix lightly then add the cocoa and jam.
Grease a pan with butter and line it with flour (or line it with baking paper), pour the composition and put it in the preheated oven at 180 degrees Celsius.
Separately, make the icing by melting the chopped chocolate together with the butter and milk over low heat.
When the cake is ready, cool it and then pour the icing.