Preheat oven to 170–180°C and line a 12-hole muffin tray.
In a large bowl, combine carrot, apple or pear, banana, oil, sugar or honey, eggs, vanilla and orange juice. Mix well.
Add sultanas, walnuts (if using), cinnamon, flour, salt, baking powder and baking soda. Mix gently until just combined.
Divide evenly between muffin holes and top with crumble or sliced fruit if using.
Bake for 25 minutes or until golden and cooked through.
Cool slightly… then devour
