Whisk together the oat milk, corn flour, and syrup so no lumps remain.
Cook, stirring, over medium heat until thickened, then pour into a ramekin and leave in the fridge to set for 2-3 hours.
For the compote, heat raspberries with a dash of water in a pot or microwave (with optional sweetener) until jammy. Leave to cool.
Serve Panna Cotta topped with raspberry compote!