Heat waffle iron.  In a large bowl, whisk together oil, sugar, sweet potato, and vanilla until smooth.  In a medium bowl, combine flour, baking powder, salt, cinnamon, ginger, and nutmeg.  Stir the dry ingredients into the wet ingredients until just combined.  Stir in oats.  Spray waffle maker, then pour batter in, spreading out gently to fill each indent (mine was 1/4 cup per indent and made 7).  Cook for 4-6 minutes until firm and golden brown.  Transfer to a wire rack to cool.