1. Place 12 paper muffin cases into a muffin tin.
2. Turn on the oven to 200c (gas mark 6).
3. Prepare the topping by rubbing the butter into the flour. Add the Quaker Oats, coconut, or ginger and sugar (60g).
4. In a large mixing bowl, place the flour, baking powder, caster sugar (100g), chopped toasted hazelnuts, pureed mango and chopped mango.
5. In a measuring jug, mix together the egg, oil, and milk with a fork.
6. With a wooden spoon, gently mix the egg mixture into the dry ingredients. (Do not beat or you will make the muffins too tough).
7. Pour the mixture into the paper muffin cases.
8. Spoon the crumble mixture on top of each muffin and gently press down.
9. Bake for 20 - 25 minutes until well risen, golden brown and set in the middle.
10. Cool on a wire baking tray.