Preheat oven or air fryer to 180°C (350°F).
Lightly grease a heat-safe mug or ramekin.
In a bowl, whisk together almond milk, melted vegan butter, vanilla extract, and maple syrup.
Add flour, cornstarch, baking powder, turmeric (if using), and salt. Whisk until smooth and lump-free.
Pour the batter into the greased mug (fill only ¾ full). Tap gently to remove air bubbles.
Oven: Bake for 12-15 minutes until puffed and golden.
Air Fryer: Bake at 160°C (320°F) for 10-12 minutes.
Let cool slightly, dust with powdered sugar, and serve.