Preheat the oven to 350 F, grease and flour three 8” baking pans and set aside
In a large mixing bowl, whisk together the flour, granulated sugar, brown sugar, cinnamon, baking powder, baking soda, salt and ground nutmeg; set aside
Add the canola oil, melted butter, eggs, and vanilla to a separate mixing bowl and whisk to combine
Pour the oil mixture into the flour mixture and stir until the dry ingredients are just moistened.
Fold in the carrots and walnuts.
Fold gently until evenly distributed through the batter
Evenly divide the batter between the three prepared pans, smoothing it into even layers
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean
Allow to cool in the pan for 10 minutes before flipping out onto a wire rack to cool completely.
For the frosting:
In a large bowl, cream together the butter and cream cheese until light and fluffy
Add the powdered sugar, one cup at a time, mixing well after each addition
Add the vanilla extract then mix on high for 1-2 minutes, or until frosting is light and fluffy.
Once the cake is completely cooled, use a serrated knife to remove the domes if necessary, then generously spread the frosting between the layer of cakes
Then generously spread the frosting on the sides and top of the cake
Pipe a design along the top of the cake, then press the walnuts into the frosting along the sides of the cake.
Allow to chill in the refrigerator for at least 1 hour to make slicing easier