Preheat your oven to 170C (fan) 190C / 375F / Gas 5
Take your melted butter and pop it in a medium bowl, make sure it's warm not hot
Then add your mashed bananas, vanilla extract and eggs and whisk with a hand whisk until combined (it may look slightly lumpy form the bananas)
Then add your sugar, self raising flour, baking powder, bicarbonate of soda and mix until well combined. Do not over mix but ensure your flour is well incorporated
Add your milk and 100g chocolate chips, holding back a few for the tops
Pop your muffin or cupcakes cases into a muffin tin
Divide the batter mixture equally between your muffin / cupcake cases
Top each muffin with a few chocolate chips
Bake in your pre-heated oven on a mid to high shelf, for 13-15 minutes or until golden brown. They should spring back to the touch
Remove from the oven, cool a little and dig in
Notes
*** Nutritional information is approximate and is intended as a guide