Preheat the oven to 180°C (fan)/200°C/gas mark 6. Add 12 muffin cases to a muffin tin.
First peel and mash your bananas with a fork. Set aside.
Add 170g plain flour, 120g caster sugar, 1 tsp baking powder and ½ tsp bicarbonate of soda to a large bowl. Whisk gently until thoroughly combined.
Heat 65ml water, 65ml maple syrup and 65ml sunflower oil together in a small saucepan until just starting to bubble. Do not boil. Remove from the heat and add 1 tbsp apple cider vinegar and 1 tsp vanilla extract.
Add to the flour mixture and stir in.
Stir in two mashed bananas and 100g chocolate chips until just combined.
Spoon into the muffin cases and bake for 20-25 minutes until risen and firm to the touch.
Allow to cool in the tin for 5 minutes then transfer to a cooling rack to cool completely.