Place the oats, oat milk, vanilla extract and cinnamon in a medium saucepan and stir well.
Place over a medium heat and bring to the boil. Reduce the heat to low and simmer gently for 6-7 minutes, stirring, until thickened and the oats have softened.
Place the porridge in 3 bowls and add 2 tsp Biscoff spread to the top of each. Swirl the melting Biscoff spread on top of the porridge and add a few banana slices. Serve hot.