Wash the orange, rub dry and grate the peel. Beat the eggs, 2 tablespoons cold water, 120 g sugar and vanilla sugar until creamy with the whisks of the hand mixer. Stir in orange zest. Mix flour, ground almonds and baking powder and fold in carefully. Spread the mixture on a baking tray (32 x 39 cm) lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 12-15 minutes. Take out and let cool down
Soak gelatine in cold water. Cut the orange in half, squeeze the juice. Mix quark, honey, syrup, 80 g sugar, rum and orange juice. Squeeze gelatine, dissolve and stir in 3 tbsp. quark, stir into the remaining quark. Whip the cream with the whisks of the hand mixer until stiff. When the quark mass begins to gel, gradually fold the cream into the quark
Turn the sponge cake, remove the baking paper. Cut the sponge cake into 3 strips of equal size (approx. 13 x 32 cm). Spread 2 strips with jelly, place on top of each other and enclose with a square cake frame (approx. 13 x 32 cm). Pour in approx. 2/3 of the quark mixture and place the remaining sponge cake strips on top. Spread the rest of the quark mixture on top. Chill the slices for about 2 hours.
Melt 50 g sugar in a pot until it is golden brown. Add sliced almonds and mix. Put almond brittle on a baking tray lined with baking paper, spread it out and let it cool down. Break the brittle into large pieces. Cut elderberry slices into 8 pieces, arrange on plates and decorate with brittle and elderberry flowers
waiting time approx. 2 hours