Put the apple, sultanas and cinnamon in a saucepan with the sugar and 1 tbsp water. Cover and cook over a medium heat, stirring occasionally for 2-3 minutes until the apple becomes soft and starts to break down. If necessary, add more sugar to taste. Remove from the heat and set aside.
Place the porridge oats, milk and water in a saucepan and cook over a medium heat, stirring frequently to avoid the oats catching. After about 2-3 minutes, the porridge should start to thicken and become creamy. You can adjust the consistency of the porridge by adding more milk or water. Remove from the heat and serve in bowls.
Spoon the apple sauce onto the porridge and drizzle with syrup or honey to serve.