Preheat oven to 350°F.
Grease and flour baking pans.
Mix flour, baking soda, powder, cinnamon, nutmeg, salt.
In bowl, whisk eggs, sugar, oil, and vanilla together.
Add grated carrots, raisins, and walnuts.
Slowly fold in dry mixture until smooth.
Pour batter into pans evenly.
Bake for 35–40 minutes until golden.
Cool on rack completely before frosting.
For frosting, beat cream cheese, butter, sugar, vanilla.
Spread frosting between layers and over cake.
Garnish with nuts if desired.