Wild blueberry and vanilla cream cake

1 piece of cream cake
 Shortcrust pastry, apricot jam,
 2 Viennese sponge cake bases,
 tied forest blueberries,
 Vanilla cream base stock: milk, sugar, vanilla, egg yolk, cream powder, gelatine, cream
 Whole cake: 16 pieces, d 26 cm, height 6 cm