01 -  In a medium bowl or a mason jar, thoroughly mix rolled oats with whole milk until fully incorporated. 
 02 -  Stir in the creamy peanut butter, ensuring it is evenly distributed throughout the mixture. 
 03 -  Fold in sliced banana gently, reserving a few slices for topping if desired. 
 04 -  Cover and refrigerate the mixture for a minimum of 6 hours or overnight to allow the oats to absorb the liquid. 
 05 -  In the morning, stir the oats and top with reserved banana slices before serving chilled.