Beat butter and sugar 1 until thick and creamy. Add half the cinnamon, flour and nuts and knead well.
Form three rolls of 2 cm  from the dough and put to cool for an hour.
Cover the baking tray with parchment paper. Preheat the stove to 175 degrees Celsius (gas: level 2).
Cut each roll into slices about 2 cm thick, shape them into croissants and place them spaced out on the baking tray. Bake in the middle of the oven for 10-12 minutes until light brown.
Mix the remaining cinnamon with the sugar 2 and powdered sugar. Carefully remove the still hot croissants from the baking sheet and roll them in the sugar. Cool.