Vegan Sweet Potato Cake

1 c flour
2 c whole wheat flour
1 tsp baking soda
1 tsp baking powder
2 tsp cinnamon
¾ tsp ground nutmeg
1 T grated fresh ginger
pinch of salt
2 c cooked sweet potato puree
1 c water
¼ c vegetable oil
2 T vinegar (apple cider or balsamic)
2 tsp vanilla extract