Sort the strawberries, wash, pat dry, pluck off the calyxes and cut the strawberries into small pieces. Put them in a bowl, marinate with vanilla sugar and aceto balsamico, cover and refrigerate for about 1 hour.
For the sponge cake batter, beat eggs with a mixer, one at a time, until foamy. Sift in sugar and vanilla sugar and continue beating until sugar is dissolved. Mix flour, cornstarch, baking powder and 1 pinch of salt, sift and fold into the egg mixture with a whisk.
Spread the sponge mixture on a baking sheet lined with baking paper. Bake in a preheated oven at 180 degrees top/bottom heat for 10 minutes until golden brown. Turn out onto a damp tea towel sprinkled with sugar and carefully roll up. Let the sponge dough cool completely.
Meanwhile, whip the cream with cream stiffener, vanilla sugar and 1 tablespoon powdered sugar until stiff. Carefully fold in the strawberry pieces. Spread the slightly warmed strawberry jam on the sponge cake roulade and spread the strawberry mixture on top.
Gently roll up sponge cake roulade loosely and chill for 4 hours. Before serving, spread the roulade with whipped cream and decorate with whipped topping and strawberries.