Sweet Potato Prep: Using a vegetable cutter or sharp mandolin, peel and cut the sweet potatoes thinly. Immediately immerse in a pizza pan with 8 cups water, juice of 1 lemon (to combat oxidation blackness), 1 cup of maple syrup and a dash of vanilla extract and cinnamon and roast in an oven at 475 F for 15 to 20 minutes until the slices are just cooked when poked with a knife. (This is important because the slices will fall apart if cooked too much.) Pull the pan out and let sit on a table to cool off — this will cook the potato slices more.