Preheat oven to 350°F (175°C) and grease an 8-inch round cake pan or line with parchment paper.
In a large bowl, whisk together almond flour, coconut flour, baking powder, baking soda, salt, cinnamon, and nutmeg.
In another bowl, whisk the eggs, melted butter, almond milk, erythritol, and vanilla extract.
Combine the wet ingredients with the dry ingredients, then fold in the shredded carrots and walnuts.
Pour the batter into the prepared cake pan and smooth the top.
Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Let the cake cool completely before frosting.
For the frosting, beat the cream cheese and butter together until smooth.
Add powdered erythritol and vanilla extract and beat until creamy.
Spread the frosting evenly over the cooled cake and refrigerate until ready to serve.