Line the bottom of a 9-inch springform cake pan with parchment paper and grease the bottom and the sides. Preheat an oven to 375°F (190°C).
Separate egg yolks from whites. We will need both
In a large bowl, with an electric mixer, beat together ½ cup sugar (100g), butter, vanilla extract, cinnamon, salt, and orange zest. Add the egg yolks and beat until smooth.
In another large bowl, mix together the flour and baking powder. Add the almond flour and ground walnuts and mix again. Set aside.
In a large bowl, beat the egg whites until foamy. Add the remaining ½ cup sugar (100g) and beat until stiff peaks.
Now combine together the butter mixture, flour and nut mixture, and grated carrots. Now carefully (with a spatula) mix in the egg whites.
Transfer the mixture to the cake pan. Use a spatula to smooth out the top. Bake 1h - 1h 15 min or until a toothpick inserted into the center comes out clean. Remove from the oven and let cool in a pan for 5 minutes then turn out onto a cooling rack, peel off parchment paper, and cool completely.