Step 1

Preheat the oven to 180C/350F/Gas Line 12 muffin tins with paper cases.

Step 2

In a large bowl, mix together the oil, brown sugar, egg, buttermilk and vanilla. Fold in the rhubarb, apple, walnuts, baking powder, flour and oat bran, then spoon the mixture into the cases.

Step 3

Mix together the demerara sugar, cinnamon and nutmeg and sprinkle over the muffins. Bake in the oven for 20-25 minutes until golden brown and springy to the touch.