Preheat oven to 340 F / 170 C. Line two 6 inch round cake tins with parchment paper.
In a medium mixing bowl mix together the almond flour, baking powder, baking soda, cinnamon, nutmeg and powdered erythritol.
In a separate bowl whisk together the eggs, oil and vanilla.
Combine the wet and dry ingredients, along with the grated carrots and crushed walnuts. Stir until well combined.
Divide mixture between the prepared cake tins.
Bake for 30-45 minutes until an inserted skewer comes out clean.
Remove and allow to cool in the tin for 10 minutes before turning out onto a cooling rack to cool completely.
To make frosting: Add cream cheese, butter, cream, powdered erythritol and vanilla into a food processor and blend until smooth and fluffy.
To assemble: Slice the tops off the cold cakes to level. Place one layer of cake on a serving plate and top with a layer of frosting. Top with the remaining layer of cake and finish off with a layer of frosting on top of the cake. Sprinkle with chopped walnuts.