In a microwave-safe bowl melt butter.

In a medium bowl and add oats, brown sugar, vanilla extract and melted butter. Stir until oats are completely coated with butter.

In a microwave-safe bowl melt chocolate chips and peanut butter together (about 1 minute at 60%).

Place all of oats mixture (except 1/2 cup) in a 7 x 12 x 2 inch baking pan.

Cut banana into 1/2 inch circles and place on top of oats mixture.

Pour melted chocolate and peanut butter mixture over top of bananas and spread carefully over entire surface.

Sprinkle remaining oats mixture over top of chocolate peanut butter.

Cover and refrigerate for about 2 hours.