Preheat waffle maker. If desired, preheat oven to 200° to keep batches of waffles warm.
Place apple sauce, milk, butter, eggs, maple syrup, and vanilla extract in a blender.
Sprinkle in the whole wheat flour, baking powder, cinnamon, and salt.
Blend until just combined, pausing the blender to scrape down the sides as needed.
Cook the batter according to your waffle maker's instructions.
If desired, place waffles on a baking sheet and keep warm in oven. Enjoy immediately with your favorite waffle toppings.