Measure flour, sugar, baking powder, salt and chocolate chips into a large bowl. Mix thoroughly and make a well in the center. Beat the egg in a small bowl until frothy. Mix in milk oil and mashed bananas. Pour into well. stir. Mixture will be lumpy. Line muffins tin with paper liners and fill 3/4 full.
Bake at 400 degree for 20-25 minutes.