Wash and dry the raisins. Put them into a sealable glass. Fill the glass with rum. Add the cinnamon stick and let the raisins soak on a dark and cold place for 3 to 4 days. Shake the glass once a day.

For the dough: Put the flour and the baking powder into a bowl. Add the orange zests, the butter and the egg. Knead everything into dough. Add the rum raisins.  Put the dough into the fridge for about 30 minutes.

Preheat the oven to 180 degrees. Shape a roll out of the dough and divide it into equal parts. Roll the dough parts to tiny croissants. Put them onto a baking sheet with baking paper. Spread the egg yolk onto the croissants and bake them in the preheated oven at 180 degrees for 15 minutes.