For the gingerbread houses, heat syrup, butter and sugar while stirring until everything is dissolved. Leave to cool for about 10 minutes. Dissolve the potash in 3 tbsp. hot water and mix with flour, spices and ammonium bicarbonate.
Add the syrup mixture, knead everything with the dough hooks of the mixer to a smooth dough. Cover and chill for about 30 minutes.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line two baking trays with baking paper. Roll out gingerbread dough between two layers of cling film 3-4 mm thin. Cut out 20 rectangles (6 x 7 cm).
Distribute on a plate with a distance of 3-4 cm to each other. Knead the rest of the dough again, roll out. Cut out 10 gable sides (6 cm wide, 8 cm high). Also place on the other tray with a distance between them.
Bake in a hot oven for 10-12 minutes one after the other. Leave to cool on the trays.
Preheat the oven for the cake (electric oven: 175 °C/circulating air: 150 °C/gas: see manufacturer). Grease a springform pan (20 cm Ø). Chop the cherries. Cream butter with sugar, vanilla sugar, orange zest and 1 pinch of salt.
Stir in the eggs one by one. Mix 150 g flour, spelt flour, baking powder, almonds and spice. Alternately stir the buttermilk into the fat-egg mixture. Fold in the cherries. Pour into the mould and smooth down.
Bake in a hot oven for 50-60 minutes (stick test after 50 minutes). Remove from the oven and leave to cool in the mould on a cake rack. If necessary, cut the cake straight at the top.
Sift 500 g icing sugar into a bowl. Add the egg white and mix with the whisks of the mixer to a thick glaze. If necessary add some more water. Remove the cake from the mould. Put about half of the icing on the cake and spread.
Sprinkle with silver sugar and sugar pearls and let dry.
Fill the remaining casting into the disposable piping bag. Glue 4 rectangles and 2 gable sides together with the cast to form a house. Leave to dry. Decorate the houses with the remaining casting. Sprinkle with silver sugar.
Decorate the cake with a gingerbread house and if necessary cinnamon sticks and rosemary. Dust everything with icing sugar.