Pour non-dairy milk and amasake in a pan. Sprinkle agar agar over the top. Heat to a simmer without stirring. Simmer for 10 minutes or until flakes dissolve. Add kudzu. Stir briskly with a whisk until mixture thickens. Add syrup, cinnamon, allspice, sugar and stir again. Remove from heat. Stir in the vanilla extract. Pour into 8 by 8 inch pan and let set at room temperature or in the refrigerator for about an hour. Once set, run the mixture through the blender or food processor for a few seconds to create a creamy pudding texture. Pour into individual serving dishes and sprinkle with grated nutmeg.