Mix the flour, salt, sugar and yeast in the food processor bowl. Pour in the oat milk, knead for approx. 5 mins. using the dough hook on a food processor. Gradually add the vegan butter and continue to knead for approx. 5 mins. Cover the dough and leave to rise at room temperature for approx. 1 hr.
Divide the dough into 8 portions, shape into balls, place in the prepared tin. Cover and leave to rise again at room temperature for approx. 30 mins. Combine the oat milk, maple syrup and cornflour, use to glaze the brioche.
Approx. 25 mins. in the centre of an oven preheated to 180°C. Remove from the oven, allow to cool slightly, remove from the tin and leave to cool completely on a rack.