For the butterfly fruit tart, first preheat the oven to 150 °C and grease a fruit tart pan (shallow, corrugated baking pan).
For the sponge cake base, beat egg whites with 80 g sugar until stiff. Beat the remaining sugar with vanilla sugar, egg yolks, water and lemon zest until foamy. Slowly stir in the flour and oil, finally gently fold in the beaten egg whites.
Pour into the prepared cake pan and bake for about 45 minutes. Approximately halfway through the baking time, increase the temperature to 170 °C.
Remove the pan from the oven, let cool for 10 minutes, then remove the cake base from the pan and let cool completely.
Strain the tangerine wedges, measuring out 3 tablespoons of juice.
Meanwhile, prepare vanilla pudding for the cream, let cool to room temperature (cover with plastic wrap if necessary to prevent a “skin” from forming).
Whip the mascarpone with a hand mixer until fluffy, stir in the vanilla pudding in several, small portions. Mix in tangerine juice and beat the cream until it is nice and smooth. Sweeten additionally with powdered sugar to taste.
Spread the mascarpone cream on the cooled cake base. Now place two tangerine wedges next to each other – thick wedge side to thick wedge side – so that they form a butterfly shape. Cover the cake with butterflies all around. Place two dried flowers on each as “antennae”.
Refrigerate the butterfly fruit tart until ready to serve.