Preheat oven to 200C.
Line your muffin tray.
Whisk together salt, sugar, flour, and baking powder.
Add melted butter, egg, vanilla extract, and mashed bananas into flour mixture.
Mix until almost combined.
Add chocolate chips and fold about 4-5 times.
Your batter should still be lumpy, do not over-mix or you'll get tough muffins.
Divide batter into muffin liners.
Bake 13-17 minutes. (Mine took about 15 minutes)
Allow to cool in pan for 5 minutes before transferring to wire rack to cool completely.