Heat the oven to 190C/375F/gas mark 5. Halve and core the pear and place cut side up in a small roasting dish, drizzle with the honey and lemon juice and dot with the butter, sprinkle over a little cardamom or cinnamon. Roast for about 20 minutes until softened, basting occasionally with the roasting juice.
Meanwhile, mix the oats, milk, water and vanilla paste in a saucepan; cook over a low heat for about 8-10 minutes, stirring often, until the coats are creamy and soft and the porridge has thickened. Add a little extra milk if needed to thin.
Serve the porridge topped with the roasted pear and a little of the roasting syrup, a drizzle of honey, a handful of chopped nuts and a pinch of cinnamon.