Grease and preheat the waffle iron according to the manufacturer's instructions. Preheat the oven to 200℉
Place the oats into the blender with the baking powder, baking soda, salt, cinnamon, nutmeg, and ginger. Pulse until the ingredients are nice and combined together. Pour out this mixture into a mixing bowl and set aside.
Place the milk, eggs, sweet potato puree, and vanilla extract in the blender. Add the flour/oat mixture on top of the wet ingredients. By placing the wet ingredients on the bottom of the blender, the batter will come together much easier. Blend until the batter is smooth and all the ingredients are evenly incorporated. This is a thicker batter. However, if too thick, add up to 3 tablespoons of additional milk.
Ladle ⅓-1/2 cup of the batter unto each waffle iron (use the amount directed per your waffle maker) and cook until golden on both sides.
Remove the cooked waffles from the waffle iron, place them onto a baking rack on a sheet pan, and keep warm in a 200℉oven until serving. Repeat until the batter is gone, greasing the waffle iron in between each batch.
Serve with toasted walnuts, maple syrup, and whipped cream if desired.
Oven Directions: Preheat the oven to 400 degrees F. Pierce 2-3 sweet potatoes with a fork several times then place them on a sheet pan lined with foil. Bake the potatoes until fork tender, about 40-50 minutes. Once baked, let cool slightly, remove skins and blend or mash the flesh of the potatoes with a fork until smooth.
Instant Pot Directions: Pierce 2-3 sweet potatoes with a fork several times then place them on a trivet inside the inner pot of an electric pressure cooker. Pour 1 cup of cold water into the instant pot. Set to cook on high pressure for 18-27 minutes, depending on the size of your potatoes, following my recipe for Instant Pot Sweet Potatoes. Once the cooking time has elapsed and pressure has been released, let the potatoes cool slightly, remove the skins and blend or mash the flesh of the potatoes with a fork until smooth.
Notes
Oats: You can use old-fashioned regular oats or quick-cooking oats for these sweet potato waffles. Do NOT use steel-cut oats.Sweet Potato Puree: Instead of sweet potato puree, you can use canned 100% pumpkin puree.Buttermilk: To make homemade buttermilk, combine 1-½ teaspoons lemon juice or apple cider vinegar with 1-¼ cup of any variety of non-dairy or regular milk and let sit for 5 minutes before using. Storage: Store leftover cooled waffles in an airtight container in the refrigerator for up to 4 days. Alternatively, freeze for up to 3 months. Toast in a toaster or toaster oven to reheat. The total time for this recipe does not include the time it takes to make the sweet potato puree.