Peel, wash and roughly grate the carrots. Separate eggs. Beat egg whites until stiff, gradually add sugar. Fold in egg yolk and butter. Add flour, hazelnuts, baking powder, orange peel and carrots to the egg mixture. Pour the dough into a greased, floured fat pan of the oven (30x40 cm). Bake in the preheated oven (electric: 175 °C/ gas: level 2) for 35-40 minutes.
Remove and let cool for about 1 hour. Stir orange juice and icing sugar until smooth and spread on the cake. Let dry for 1 hour. Knead marzipan with green food colouring. Press the marzipan in portions through the garlic press and place it on the pieces as small nests. Place a sugar carrot on each piece as desired