Steps

• TO PREPARE THE SPONGE CAKE (FOR A 14X11 INCH PAN)

  Preliminary: take the eggs out of the fridge at least 2 hours before.

  Combine the potato starch with the flour and sift them together.

  Grease and flour the baking pan, dimensions 14×11 inches

  Preheat the static oven to 356°F

• Preparation: To prepare the book cake, the first thing to do is to start with the sponge cake.

  Take the eggs, and separate the yolks from the whites.

  

• Place the egg whites in the bowl of the stand mixer and add about 4.2 oz of sugar and start beating them at medium speed until they are whipped, but not stiff, until the mixture is frothy, set aside

  

• Now let’s take care of the yolks.

  Add the remaining sugar to the yolks and beat them with an electric whisk until the mixture appears frothy. Add the vanilla seeds, scraping them with a knife from the pod. If you can’t find the vanilla pod, add the vanilla essence.

  

• Now stop everything and gently combine the beaten yolks with the egg whites and mix with a spatula from bottom to top to prevent the mixture from deflating

• At this point, add the previously sifted powders to the egg mixture and, with the help of a spatula, gently combine all the ingredients with upward movements. This is the most important moment to have a soft and high sponge cake

  

• Pour the mixture into the previously greased and floured baking pan, and level the surface with a spatula. Bake in a preheated static oven at 356°F for 60-70 minutes. When it has cooled, simply remove it by turning it upside down, and place it on a wire rack

• Whip the cream and set it aside in the fridge

  

• In a bowl, place the yolks and powdered sugar, then work them with the electric whisks for about 1 minute until the mixture is light.

  

• In a second bowl, put all the mascarpone, and add the mixture in 3 parts, each time working with the electric whisks for a few moments. Be careful not to deflate the cream.

  

• Add 2/3 of the whipped cream (the rest will be used to garnish the edge of the cake). Mix with a spatula from bottom to top, trying not to deflate the mixture which should be very thick.

  

• Trim the sponge cake on all 4 sides, then divide it into two horizontally to create 2 bases.

  

• Transfer 1 base onto a large square plate and soak with half the amount of syrup.

  

• Fill with half the cream (keeping a bit higher in the center). Distribute the chocolate chips, or alternatively various grains or pieces of fruit. Cover with the second sponge base also soaked with the syrup.

  

• Fill with the remaining cream, reaching perfectly to the edges and corners (and also filling the empty spaces if there are any between the 2 sponge bases),

  

• then with a long-bladed knife try to spread the cream well, place the blade in the center, and press, giving it a line that suggests an open book.

  

• Decorate the entire edge with whipped cream, using a piping bag, then spread it with a knife blade, and finally pass a silicone brush over it to create lines that resemble the pages of a book.

  

• Now you can stop with the decorations or proceed as you wish. I used an airbrush with food coloring, and decorations purchased online suitable for the party, also with melted chocolate I wrote on the cake.

  

• Here is the Book Cake for Communions and Confirmations ready. My nephew was thrilled.