Combine the coconut milk, arrowroot powder, sugar, and cashews in a saucepan. Stir to combine. Bring to a simmer (low boil) over medium heat while stirring (this can take up to 5 minutes). Simmer for 1 minute. Remove from heat. Don't worry about lumps in the sauce if they occur.
Add the cream mixture to a high-speed blender. Add the nutritional yeast flakes, vanilla, and pinch of turmeric (for color). Blend until creamy.
Pour the cream into 4 brûlée dishes or ramekins (or 8 smaller containers). Place in the fridge to set for at least 2 hours to overnight (the longer it sits the thicker the cream will become).
Before serving, sprinkle the top of each with approximately 1 tablespoon granulated sugar and make sure the entire surface of cream has sugar over it. Use a kitchen torch to carmelize the sugar and create a crispy top coating. Serve immediately or refrigerate for up to an hour before serving.
If you don't have arrowroot powder, you can substitute cornstarch.
For Chocolate Creme Brûlée
Add up to 1/4 cup cocoa powder to the milk mixture (and leave out the ground turmeric).
Regarding Coconut Milk
Use full-fat coconut milk. The label should read between 13 and 15g of fat. The amount of fat in each can varies which will have an impact on how creamy the custard is. Keep your coconut milk in the fridge so the fat hardens. Then you can scoop the fat from the can. If your can has 1 cup of fat that's good. If your can has less than 1 cup, use 1.5 tablespoons arrowroot powder.
To make ahead, prepare the custard and pour it into serving dishes. Cover tightly and refrigerate for up to 3 days before serving.
Burning Sugar Options
Don't have a kitchen torch? You can use your oven broiler to burn the sugar. Simply, move the oven rack to the highest rack in the oven. Heat up the broiler so it's very hot. It helps if the custard itself is well chilled. Just be sure to set it out at room temperature for a few minutes so the ramekin doesn't crack. You won't achieve the same golden color as with a torch, but this works. I've also read that a grill lighter (the ones with a long wand) can burn the sugar topping as well. However, it seems like that would take a while so it may not be practical. Once the sugar coating is done, let it sit for a few minutes before eating it, so you don't burn your mouth.