In a bowl, dissolve the cornstarch in 2 cups grape juice, then mix the rest of the must. In a heavy pot, heat the grape juice in medium heat, stirring with a wooden spoon. Stir constantly, until it boils and thickens.
Pour into individual bowls or soup plates and let cool completely. Just before serving, sprinkle with sesame seeds, chopped walnuts, and cinnamon.
The jelly will keep for about a week in the refrigerator.
NOTE: Juice fresh grapes to get about 12 cupss of juice, or use commercial grape juice. Add 6 cups sultanas and bring to a boil. Simmer for 20 minutes. Process in the blender in batches and pass the liquid through a sieve, squeezing the the sultanas to extract all their juices. Measure to get the 9 cups.
