Peel and rough-cut sweet potatoes and put them in 4-quart saucepan with 2 cups water. Cover, bring to a boil, and cook until potatoes are tender, about 25 minutes; drain well.
In medium saucepan, combine apple juice, 1/2 cup water, and agar-agar flakes and allow to sit 10 minutes. Bring to a slow simmer over medium heat and cook for 10 minutes.
In medium bowl, combine barley malt, maple syrup, 1 tablespoon vanilla extract, salt, cinnamon, nutmeg, allspice and cloves. Add to agar-agar mixture and stir well.
In separate bowl, thoroughly dissolve kudzu in 3 tablespoons water and stirring briskly with a whisk, add to agar-agar mixture. This will thicken it to form a syrup; continue to cook it at a low simmer for 15 minutes.
Purée drained sweet potatoes in a food processor with the remaining 1 tablespoon vanilla extract. Pour syrup into the sweet potatoes and process several minutes or until smooth. Transfer to shallow casserole, bring to room temperature and then refrigerate until set, about 1 hour. Blend pudding in a food processor for several minutes. Place chopped pecans on a baking sheet and toast in a 350°F oven for 10 minutes. Spoon alternate layers of pudding and Pecan Cream into parfait glasses. Top each with chopped toasted nuts.