Separate 5 eggs. Beat the egg whites, 1 pinch of salt, 3 tablespoons of water, 1 packet of vanillin sugar until stiff with the whisks of the hand mixer. Sprinkle 125 g sugar. Stir in the egg yolks. Mix 75 g flour, 50 g starch, 50 g almonds and 1 tsp. baking powder.
Fold under the egg mixture in portions. Place on a baking tray lined with baking paper, smooth down and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 15-18 minutes. Remove from the oven, immediately turn over onto a large board, remove paper. Let it cool down.
Process the remaining egg, 1 pinch of salt, 3 tablespoons of water, 1 packet of vanillin sugar, 125 g sugar, remaining flour, remaining starch, remaining almonds and remaining baking powder as described above to make a second base, bake, turn over and allow to cool.
Pour mandarins into a sieve and drain very well. Stir the jelly until smooth, spread evenly thinly on a base. Put sour cream, 500 g cream, 75 g sugar and sauce powder into a large mixing bowl and whisk for 2-3 minutes. Pour onto the base coated with the jelly, smooth it down and carefully place the second pastry sheet on top. Press down lightly.
Whip the rest of the cream until stiff, while pouring in 2 sachets of vanillin sugar. Spread the surface of the pastry sheet evenly. Mark 30 pieces (about 6.5x7 cm) in the cream. Coarsely chop the chocolate coating and melt over a warm water bath. Remove from the hot plate and let it cool down a little.
Carefully dab each tangerine dry with kitchen paper. Place 2 mandarins with the round sides facing each other on one piece to form a butterfly. Cover all marked pieces in this way.
Pour the couverture into a disposable piping bag. Cut off the tip just short. First inject small dots and then the butterfly antennae. Allow to dry a little and arrange on a board.