Preheat the oven to 200 °C top/bottom heat.
Cut the pumpkin into pieces and chop very finely. Mix hazelnuts, baking powder, egg white powder and orange zest together.
Beat eggs with xucker, cane sugar and salt until well blended. Slowly fold in pumpkin and nut mixture and pour into prepared loaf or cake pan. Be careful, the batter is quite runny.
Bake on the middle rack for about 50 minutes, then test for doneness, and let rest in the turned off oven for another 5 – 10 minutes if necessary.
Let the cake cool and decorate with chocolate icing.