Preheat the oven to 180°C. Line a muffin tin with paper baskets or put 12 silicon muffin cases on a baking sheet.
Mash the bananas with a fork. Add the egg and oil to the bowl. Mix until well combined. Then stir in the grated apple.
Add the flour, sugar, ginger and cinnamon. Mix until well combined. Add the milk and combine - you might need to add more if the mixture is too thick.
Fold in the sultanas, then spoon the batter into the muffin cups.
Bake the muffins for approx. 20 minutes, until a skewer inserted into the centre of a muffin comes out clean.
Let the muffins cool in the tin for 5 minutes, then transfer them to a wire-rack to cool completely.