Place milk or cream, vanilla bean and scraped seeds in a small heavy saucepan. Cook over medium heat just until bubbles form around the edge of the pan, taking care not to scorch the milk. Remove from heat and let stand 20 minutes to infuse the vanilla flavor. (Rinse the bean with water, pat dry and store in sugar if you wish.)

In a small bowl, whisk together the dried cane juice, cornstarch and salt, then gradually whisk it into the milk. Bring the mixture to a boil over medium heat, whisking constantly, until it thickens, about 2 to 3 minutes. Pour into four goblets or bowls and cover with plastic wrap to prevent a skin from forming. Chill at least two hours before serving. Serve cold or at room temperature.