For the gingerbread house, heat the butter, sugar, honey, salt and water in a saucepan while stirring so that the sugar dissolves, then allow to cool. Stir in flour, baking powder, cocoa and gingerbread spice and let the dough rest a bit.
Cut out the shapes for the house (walls, roof) from cardboard. Knead the dough again, and roll it out with a rolling pin. Place the cardboard on top and cut out the individual parts.
Brush the gingerbread with a little water and bake at approx. 180 °C for 15 – 20 minutes (depending on thickness).
For the icing, whip the egg white until it is stiff, then stir in the powdered sugar. The mixture should be firm. The mass can be colored with a little food coloring.
Pour the mixture into a piping bag and glue the individual parts together. Decorate the house (windows, doors, roof tiles, …)