LINE 9-inch-square baking pan with heavy-duty foil.
HEAT cream in a medium saucepan over medium-high heat for 1 to 2 minutes or until bubbles appear around edges. Remove from heat. Add morsels; stir until smooth. Cool, stirring occasionally, for 10 to 12 minutes. Add marshmallows; stir to coat. Gently stir in graham cracker pieces until combined.
SPREAD mixture into prepared pan; press down lightly. Refrigerate for 2 hours or until firm. Cut into bars.