Melt the butter and let it cool down. Clean, peel, wash and roughly grate the carrots. Measure 2 1/2 cups (450 g) of grated carrots. Stir sugar and eggs for about 2 minutes until creamy.
Add the oil and butter and continue stirring for about 2 minutes. Mix flour, baking powder, almonds and salt, sieve and stir in. Fold in the carrots. Grease a wreath mould (26 cm Ø) and dust with flour.
Pour the dough into the tin and smooth it down. Bake in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 hour. In the meantime reduce 8 tablespoons of orange juice by half.
Take the cake out of the oven, let it cool down for about 5 minutes and turn it over onto a cake rack. Turn the cake over, place it on a cake rack and place it on a baking tray. Prick the cake several times with a wooden skewer and soak it with the orange juice.
Let it cool down. Stir icing sugar and 2-3 tablespoons orange juice until smooth. Spoon the icing onto the cake. Peel the orange peel with a zest ripper. Peel the remaining orange peel so that the white skin is completely removed.
Use a knife to remove the pulp between the partitions. Decorate the cake with orange pieces and zests. Place the cake on a cake plate and cut into pieces.