Place all ingredients except milk into a large bowl. Start by adding 1/4 cup of milk and mixing all ingredients together. Depending on how much water is retained in the potatoes will influence how much milk you will need. Add additional milk up to 3/4 cup. Batter should be thick.
Pour batter into waffle iron, wait to cook. Remove immediately and serve warm. Or allow to cool and put into freezer bags for busy mornings. Cooked frozen waffles can be reheated in a toaster.
To make sweet potato puree: You will need 1-2 medium sized sweet potatoes. Wash and peel sweet potatoes. Place prepared potatoes in a medium size pan, cover with water, and place on the stove. Bring pan to a boil and continue to boil until the sweet potatoes are tender when pierced with a fork, about 20 minutes. Cut sweet potato just enough to put into a food process or blender. Add a little bit of reserved water until sweet potatoes are creamy.