In a small bowl, stir together the cornstarch with 3 tablespoons of water until smooth.
In a medium saucepan, add the soy cream, oat milk, ⅓ cup (70 g) of the sugar, the pudding powder, scraped vanilla seeds and pod, turmeric (if using), and cornstarch slurry and whisk to combine.
Bring the custard to a boil over medium-high heat, stirring occasionally in order to prevent the bottom from burning. Reduce the heat to medium and simmer for about 5 minutes, until the mixture thickens (it should resemble pastry cream or vanilla pudding).
Remove the vanilla pod, and then pour the custard evenly into four ramekins and place them in the fridge to set for at least 4 hours, or overnight.
Remove the crème brûlées from the refrigerator about 30 minutes before serving (the custard will be too stiff fresh from the fridge). Sprinkle the top of each dessert with a thin layer of the remaining sugar (about 1 tablespoon per serving). Using a kitchen torch, melt the sugar on each dessert until it’s crunchy and caramelized. Serve immediately.