Preheat the oven to 180°C (approximately 350°F). Line a baking sheet with parchment paper.
Peel and finely grate the carrots. Mix the carrots and lemon juice.
Separate the eggs. Beat the butter and sugar until creamy. Gradually stir in the egg yolks. Beat the egg whites with the vanilla sugar and salt until stiff. Mix in the flour, baking powder and cinnamon. Fold the egg whites and carrots into the egg yolk mixture. Spread the batter onto the baking sheet and smooth. Bake for about 50 minutes, until golden brown.
Remove from the oven and cover with a kitchen towel. Let cool. Cut into pieces and serve.