Transfer the potatoes to a food processor. Add the maple syrup, plant milk, tahini, vanilla, cinnamon, and salt (if using). Puree until smooth.
Chill in the refrigerator until ready to serve.
To make the waffles, combine the plant milk, applesauce, aquafaba, and vinegar in a bowl. Stir to combine.
Combine the oats, flour, sugar, baking powder, salt, and cinnamon in a food processor. Pulse until a coarse meal forms. Add the wet ingredients into the dry ingredients and mix well. Let the batter stand for 5 minutes.
Heat the waffle iron according to the manual instructions. Add ½ cup of batter to each mold in the waffle iron. Cook for 5 to 7 minutes. Let cool for a moment.
Serve warm with the Sweet Potato “Butter.”
For best results, use a waffle iron with a nonstick surface. If the waffles get soft, reheat in a toaster or oven at 350˚F for 10 minutes, until crispy