Add 2 cups unsweetened soy milk, 2 grams agar agar, and 2 tablespoons evaporated cane sugar to a pot. Split 1 vanilla bean and scrape out the seeds, putting the seeds and the pod in the pot.
Heat over medium-high heat, stirring constantly until the mixture comes to a rolling boil (this will take 3-4 minutes).
Divide the soy milk mixture into small ramekins or bowls, passing it through a tea strainer to remove any chunks of vanilla or coagulated soy proteins. Cover and chill in the fridge for at least 2 hours.
To make the black sugar syrup, add 25 grams kokutou, 25 grams evaporated cane sugar, and 1 tablespoon water into a small pot over medium heat. Cook until the mixture comes to a boil and the sugar has dissolved. If your sugar is not in powder form (i.e., it comes in chunks), you'll need to use more water and give it time to dissolve. Then you can boil it down to reduce it into a thick syrup. Let the syrup cool.
To serve, you can either pour the syrup straight into the ramekins or unmold the dairy-free panna cotta first and then drizzle the sauce on top. Garnish with fresh berries (like blackberries or strawberries) for a pop of color.
