1. In a large pot filled with water, boil potatoes over high heat about 45 minutes, or until tender. Remove and allow to cool. Peel, slice in half lengthwise, and then slice horizontally into ½-inch crescents.
2. In a food processor, combine sweet potatoes, vanilla extract, sugar, cinnamon and egg whites. Process until smooth and completely combined.
3. Transfer sweet potato mixture to an ungreased 9-inch circular glass pie dish. Bake in a preheated 350 degree oven for 45 minutes. Remove and allow to cool.
4. Into each of six short parfait glasses, add one-sixth of the crushed graham crackers, spreading evenly across the bottom. Follow with one-sixth of the sweet potato mixture. Top each with ¼ cup whipped topping or whipped cream, and sprinkle with 1 tablespoon pecans.
Kewl tip: Gild these decadent, parfaits with a sprinkling (or more, if desired!) of edible 24 karat gold leaf for a truly indulgent treat! It goes to show — these delicious desserts will become a treasure in your festive holiday arsenal (please pardon the pun!).