Step 1

Spray 9 x 13 pan with non-stick spray and set aside.

Step 2

Melt butter in a large microwave safe bowl.

Step 3

Pour marshmallows into the bowl and stir.

Step 4

Place into microwave for 45 seconds, remove and stir.

Step 5

Return to the microwave and heat for another 45 seconds. Remove from the microwave and stir again.

Step 6

Pour Rice Krispies into the melted marshmallows and mix until well combined.

Step 7

Distribute evenly and press firmly into the pan.