Preheat the oven to 190 °C (375 °F). Beat eggs, sugar, vanilla sugar, and salt until light and fluffy for 5–7 minutes. Fold in flour gently. Divide batter onto lined baking sheets and bake for 10 minutes or until golden. Cool completely.

Line a salad bowl with plastic wrap. Cut the cooled sponge layers into Ø 18 cm, Ø 16 cm, and Ø 14 cm circles. Line the bowl with sponge strips, covering it fully.

Whip heavy cream until soft peaks form, then mix in vanilla sugar. Fold in cream cheese and caramelized sweetened condensed milk until smooth. Layer this cream with sponge in the bowl. Cover and refrigerate for at least 8 hours.

Beat cream cheese, mascarpone, heavy cream, and powdered sugar until firm consistency forms. This will decorate the cake.

Invert the bowl onto a serving plate. Spread a thin layer of decorating cream over the cake. Use leftover sponge scraps to create a sponge ball on top.

Pipe decorations on the cake resembling knit patterns using a star piping nozzle. Chill for an additional 2 hours before serving.