Preheat the oven to 180°C and line a baking sheet with parchment paper.
Beat the eggs, sugar, and vanilla sugar until frothy.
Add the oil and Fanta brandy, then carefully fold in the sifted flour and baking powder.
Place the dough on the baking sheet and bake for 20–25 minutes, until golden brown and a wooden skewer comes out clean.
Whip the cream with powdered sugar until stiff peaks form, fold in the mascarpone, and mix until smooth.
Spread the cream evenly over the cooled cake, arrange the mandarins on top, and dust with grated white chocolate.
Refrigerate for at least one hour, then enjoy.