In a large, microwave safe bowl, combine marshmallows and butter. Melt on high for 2-3 minutes, checking and stirring every 45 seconds or so, until completely melted.
Add rice krispies, apples, and white chocolate chips. Stir until evenly combined.
Pour in a foil or wax paper lined 13"x9" pan and spread with your finger.
Dust with cinnamon.
Allow to cool for at least one hour before cutting into squares.