In a bowl mix together the milk, pumpkin, eggs, oil, sugar and vinegar.
Sprinkle the flour, baking powder, baking soda, allspice, ginger, cinnamon, and salt over the pumpkin mixture and stir lightly just until no dry spots remain.
Heat a lightly oiled waffle iron and cook according to the directions for your particular model.
Melt the butter over medium heat in a semi-large pan.
Stir in the sugars, lemon juice and evaporated milk, bring to a boil and let cook for 1 minute. Remove from heat.
Stir in the baking soda, mixing continuously until it stops foaming and stir in the pecans.