Heat up your waffle iron according to instructions.In a large bowl combine oat flour, baking powder and spices.In a separate bowl combine sweet potato, eggs, maple syrup, coconut oil, vanilla and milk.Add wet ingredients to dry and stir to combine.Stir in blueberries.Spray waffle iron with coconut oil and add about 1/2 a cup of batter to the waffle maker. Cook until waffle maker says it's complete.Top with maple syrup, nut butter or jam.These freeze well and make a great quick breakfast if you put them in the toaster in the morning.