In food processor, turn walnut halves into walnut meal, then mix it with icing sugar, set aside

In a large bowl, mix flour, icing sugar, lemon peel, baking powder until combined, then add in beaten egg that’s been mixed with 1 tbsp lemon juice. Knead in 200 g butter, until coarse crumbles, then knead in the last butter plus another tbsp lemon juice

Divide dough into 3 equal portions. Into one, knead in cocoa powder

Roll each portion into a square, and melt apricot jam in microwave for 35-45 seconds

Lay 1 dough square on pan and brush with half of the melted jam. Sprinkle top with half of the walnut meal, then lay the chocolate dough. Brush top with the leftover jam, then sprinkle top with the leftover walnut meal

Lastly, top with the last dough square and poke holes all over

Bake cake on preheated 350 F for 30-35 mins

Cool cake in pan for 25 mins

Make icing by using double boiler. Mix yolks and icing sugar on double boiler until hot to the touch, then quickly spread icing on cake

Let stand until icing firm up before slicing