In a medium saucepan, whisk together cornflour and 50ml of plant milk. Once smooth, add the remaining plant milk, vanilla extract and caster sugar.
Place over medium low heat and stir constantly until the custard thickens.
Remove the pan from the heat then immediately add the vegan butter. Stir vigorously until fully melted and incorporated into the custard.
If serving warm, serve immediately. Alternatively, cover the surface of the custard with plastic wrap and leave to cool to room temperature then store in the fridge.
