Grease the bottom and sides of two 18cm cake tins (7-inch cake tins) or line them with parchment paper.
Cut the orange in half and squeeze the juice from one half, removing all seeds.
Pre-heat the oven to 350° F / 175° C.
Whisk egg whites in a bowl until medium peaks form. Mix in almond milk, coconut sugar, apple cider vinegar, vanilla extract, coconut oil, grated carrots, half the grated orange rind, and juice of half an orange.
Gently add egg yolks and whisk on medium.
In a bowl sift together almond flour, almond meal, baking powder, baking soda, salt, cardamom powder, nutmeg, and the ground ginger and cinnamon.
Gently combine the dry ingredients with the wet ingredients. Fold in the chopped walnuts, reserving 2 tablespoons for the garnish.
Divide the batter evenly between two baking tins. Bake for about 35 minutes or until the top is brown and a toothpick inserted into the center comes out clean.
Once baked, remove the cake from the oven and let them cool on a rack before taking out of the tins.
After cooling, spread a third of the frosting on one cake layer. Place the second layer on top and use the remaining frosting to cover it.
Sprinkle the reserved walnuts on top and refrigerate the cake for at least 30 minutes before serving.