Preheat oven to 350°F degrees.
Grease two 9-inch round cake pans.
Mix flour, sugar, baking soda, spices, salt.
Combine oil and eggs in separate bowl.
Add wet ingredients to dry ingredients.
Fold in grated carrots and walnuts.
Divide batter between prepared cake pans.
Bake for 40-45 minutes until done.
Cool completely on wire racks.
Beat cream cheese and butter together.
Gradually add powdered sugar and vanilla.
Frost cooled cake layers evenly.