Preheat your oven to 350°F.
Gather all ingredients, a large mixing bowl, measuring cups, a mixing spoon, a peeler for the carrots and two 9 inch round pans.
(Optional) Take a small baking pan and grease lightly with oil or butter. Add the chopped walnuts to the pan and bake in the oven for 5-7 minutes to toast.
Remove from oven once toasted and set aside.
Add flour, sugar, baking soda, salt, ground cinnamon, pumpkin pie spice, and a little over half of the toasted walnuts to the large bowl. Stir to blend dry ingredients well and set aside. The remainder of the toasted walnuts will be for topping the carrot cake.
Peel carrots and cut off ends. Chop the carrots into small to medium sized chunks. Add two cups of chopped carrots to a blender. Pulse for approximately 10 seconds or until carrots are finely grated or even mushy.
Next add the olive oil, apple cider vinegar, cold water, and vanilla extract to the blender with the pulsed carrots and pulse for approximately 10-15 seconds or until the mixture is smooth.
Pour the mixture into the large bowl with the dry ingredients and mix well.
Lightly grease the two 9 inch round pans with vegan butter and pour the carrot cake mixture into the pans.
Put the two cakes in the oven and bake for approximately 35 minutes or until your readiness test passes (see notes for readiness test).
Once the cakes are ready, remove them from the oven and allow to cool completely.
When cooled, generously layer the butter cream icing (see prep below) on top of the cake with a butter knife.
Sprinkle the remainder of the toasted walnuts on top of the cakes.
Serve yourself a slice. Job well done! Enjoy!