Preheat the oven to 180 ° C top / bottom heat. Line a deep baking sheet with parchment paper, either grease the edges of the sheet or cover with parchment paper as well.
Sieve the flour with baking powder and gingerbread spices into a bowl. Put the water, honey, margarine and sugar in a saucepan and bring everything to the boil while stirring and let it cool. Mix 4 eggs one after the other into the flour mixture, also add walnuts and orange peel.
Pour in the cooled water-honey liquid and mix everything thoroughly until it forms a smooth, thick mass. Spread this mixture evenly on the baking sheet and bake for approx. 40 minutes.