Clean, wash and finely grate the carrots. Beat eggs, sugar, vanilla sugar, lemon peel and salt with the whisk of the hand mixer until foamy. Add the low-fat curd cheese, hazelnuts, grated carrots, flour and baking powder and mix well.
Heat the fat in a saucepan. Use the handle of a wooden spoon to determine the correct temperature. If bubbles form, the correct temperature has been reached. Cut off some of the dough with two tablespoons and add it to the fat.
Bake the pastry from both sides for four to five minutes until golden brown. Remove the pastry from the fat and let it drip off on kitchen paper. Mix icing sugar and cinnamon. Serve the doughnuts dusted with it.
Results in about 30 pieces.