I got this recipe from skinnytaste.  So good and so easy!

2 Tbsp light butter spread (Smart Balance Light)

4 cups or 10 oz mini marshmallows

6 cups Rice Krispies

Spray a 9×12 pan and set aside.

Heat a large saucepan on low heat.  Melt Butter in pan and add marshmallows.  Melt on low, stirring until completely melted; remove from heat.

Add Rice Krispies and stir until combined.  Press into pan.

Yields 16 servings for 2 ww points each.