Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius). Line a 9- x 13-inch (20- x 30-centimeter) pan with Gefen Parchment Paper.

Turn your mixer on and add the whites one at a time on low speed. Add salt. Increase speed of mixer and beat until the whites start to become stiff. Gradually add 1/2 cup sugar and continue beating until glossy peaks form. Set aside. 

Beat yolks with remaining 3/4 cup sugar until light and lemony. Add vanilla sugar and oil and continue beating until mixed together well. Add potato starch (sifting in a small sifter over the mixing bowl) and mix until incorporated. 

Gently fold in egg white mixture on low speed. 

Pour batter into the prepared pan, leaving approximately 3/4 — 1 cup batter in the bowl. Add the cocoa powder and coffee to the remaining batter and mix together. Pour on top of white batter and gently swirl with a knife to marbleize. 

Bake in the preheated oven for 45 minutes or until toothpick inserted in the center comes out dry. Cool before glazing. 

Combine all glaze ingredients in a small bowl. Add more confectioners’ sugar or hot water to achieve drizzling consistency. 

Using a small spoon, drizzle all over cake. Sprinkle with almonds before glaze sets, so they will adhere to the glaze.