For the Barbie cake, beat the eggs, powdered sugar, pinch of salt and vanilla sugar until very foamy. Then add oil and water and continue beating briefly.
Mix flour, cornstarch and baking powder and stir in. Grease and flour a dome cake pan, pour in the batter and bake at 170 degrees until golden brown. Let the cake cool and turn it out.
For the fruit ingredient, puree the berries, add sugar if desired, and boil for 2 minutes. Then add gelatin according to instructions. Line 2 round bowls of different sizes or plates with plastic wrap, divide the berry mixture in them and chill until a firm sheet is formed. Cut the cake in half 2 times.
Spread the cake base with ganache, fruit insert on top, spread again with ganache, then again the cake base, ganache, fruit insert, ganache and at the end again the cake base on top. Chill the cake for 2 hours.
Then spread the Barbie cake with ganache all around and chill.
For the decoration, knead white fondant soft and cut a strip and put it on top of the dome. Cut diamond pattern and decorate with sugar pearls.
Knead yellow fondant soft, cut out the edge of the dress with edge stencil and place the dress all around the cake. Insert Barbie top into the cake and shape the dress out of fondant for the top.
Cut out sugar flowers and decorate the Barbie cake with them.