Put all the ingredients in a warm mixing bowl and stir until the oats are covered evenly with the oil and honey.
Turn out onto a nonstick baking sheet, making sure that there are no lumps. Put in the bottom of a warm oven, 110°C (225°F), Gas Mark ¼, for 4–6 hours, stirring occasionally to prevent sticking or browning.
When crispy, remove and allow to cool. Serve with skimmed milk or low-fat yogurt. Store in an airtight container. The mixture will keep fresh for several days if kept free of moisture.