Set aside 1 cup marshmallows, 3/4 cup chocolate chips and 1/2 cup crushed graham crackers to top the treats with.
Lightly spray an 8-inch square metal baking pan with nonstick spray. Cut out an 8-inch-wide strip of parchment paper and use it to line the pan, leaving enough overhang on the sides so you can use the flaps to lift out the treats. Lightly spray the parchment with nonstick spray.
In a large nonstick pot over medium heat, add the butter. Swirl around until melted, then dump in the marshmallows. Stir gently with a spatula until the marshmallows have completely melted, about 90 seconds. Remove the pot from the heat, then add the rice cereal and stir until combined. Let cool slightly, then add the crushed graham crackers and fold in gently. Add the chocolate chips and mix just barely until folded in (if you mix too much, the chocolate will melt completely).
Dump the mixture into the lined pan and press down gently so the mixture is evenly distributed in the pan. While still warm, sprinkle with the reserved marshmallows, reserved chocolate chips and reserved crushed graham crackers. Using a creme brulee torch, toast the marshmallows and melt the chocolate evenly, using a sweeping motion so the marshmallows don't catch fire, about 45 seconds.
Allow to cool completely, about 30 minutes.
Slice into squares using a warm, sharp knife and serve.