Preheat oven to 160 degrees celsius. Grease baking tray with vegan margarine.
Heat nut butter until stirable. Mix with sweet potato puree and vanilla extract in a large bowl.
Mix all the dry ingredients in a seperate bowl.
Fold dry ingredients into wet ingredients.
Put the mixture evenly onto the baking tray and bake for 20 minutes. Let it cool for about 1 hour.