Separate eggs. Beat the egg whites until stiff, adding 100 g sugar, salt and 1 sachet of vanillin sugar. Stir in the egg yolks one by one. Mix flour, starch and baking powder, sieve onto the egg cream and fold in. Line a baking tray with baking paper, place the mixture on top and spread. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: not suitable/ gas: level 3) for approx. 12 minutes.
Turn the sponge plate onto a tea towel sprinkled with sugar, remove the baking paper immediately. Let it cool down. Cut the sponge cake plate to 30x35 cm. Place baking frame or aluminium foil strips around the sponge cake. For the cream, soak gelatine in cold water. Drain the apricots and puree the fruit with the hand blender. Mix the quark with the apricot puree, 300 ml nectar, 80 g sugar, 1 packet of vanillin sugar and orange peel. Dissolve gelatine at low heat. Mix with 2 tablespoons of quark and stir into the remaining quark. Whip cream until stiff, fold in. Spread the cream on the sponge cake, smooth it down. Chill for about 4 hours.
Dissolve gelatine at low heat. Mix with 2 tablespoons of quark and stir into the remaining quark. Whip cream until stiff, fold in. Spread the cream on the sponge cake, smooth it down. Chill for about 4 hours. Wash kumquats, dab dry and cut into slices. Use a cutter (7 cm Ø) to cut out round tartlets from the sponge cake (alternatively cut into rectangles). Mix the cake glaze powder with 10 g sugar in a small pot. Gradually stir with 250 ml passion fruit nectar until smooth. Bring to the boil while stirring. Drizzle the icing over the kumquats. Coarsely chop the pistachios, decorate the tartlets with them
Use a cutter (7 cm Ø) to cut out round tartlets from the sponge cake (alternatively cut into rectangles). Mix the cake glaze powder with 10 g sugar in a small pot. Gradually stir with 250 ml passion fruit nectar until smooth. Bring to the boil while stirring. Drizzle the icing over the kumquats. Coarsely chop the pistachios, decorate the tartlets with them