In a large bowl; add the cold butter, sugar, all-purpose flour and baking powder. Use your hands to mix all the ingredients into a crumble.
Add the zest from one organic lemon and one beaten egg. Again, mix everything into a smooth and little sticky dough.
Roll the dough into a rod with a length of about 30 cm. Let the dough rest in the fridge for one hour.
Cut the rod into 30 pieces and roll them into balls. Place them on a parchment paper covered oven plate.
Pre-bake the balls in a 225 C (435 F) preheated oven for 10 minutes.
Remove the balls from the oven and remove them from the hot oven plate. Let them cool off a couple of minutes before cutting them in the middle using a bread knife. Now you could have 60 Kammerjunker. Again, transfer the cookies to the oven plate. The cut side should face upwards.
Bake the cookies for another 20 minutes at 175 C (350 F). Let them cool off and they are done.
keep the Kammerjunker in an airtight container to keep them fresh.