Preheat oven to 325 degrees F. Butter the sides and line (2) 8" cake pan bottoms with parchment paper and set aside.
In a medium bowl add nut butter, eggs, cinnamon, pumpkin pie spice, baking soda, baking powder, salt, vinegar, vanilla, chopped nuts, grated carrots and sweetener.
Blend with whisk or hand mixer until well incorporated.
TASTE FOR SWEETNESS and adjust if needed.
Divide batter between both pans and spread batter out evenly.
Bake for 16-18 minutes or until toothpick inserted in the center comes out clean. DO NOT OVERBAKE!
Allow cakes to cool for 5 minutes in pans before running a blunt knife around edges and inverteding onto a cooling rack. Allow to cool completely.