In a large bowl, combine flour, baking powder, cinnamon, allspice, ginger, salt, and xanthan gum (if using), mix well. Add the pumpkin, milk, egg yolks and butter. Mix well to combine.
In a separate bowl beat the egg whites with an electric mixer, until soft peaks form. Using a large spoon or spatula, gently fold the egg whites into the pumpkin/flour mixture.
Into a heated, electric waffle maker, pour a ladle-full of batter into the center of the waffle plate. Cook according to manufacturer instructions.
Serve with choice of toppings. We like syrup and whipped cream, and sometimes walnuts. :)