PREPARATION:

1. Line 8- or 9-inch square pan with aluminum foil, leaving 2-inch overhangs on 2 sides. Generously grease or spray with nonstick cooking spray.
2. Melt marshmallows and margarine in medium saucepan over medium heat 3 minutes or until melted and smooth, stirring constantly. Remove from heat.
3. Add cereal; stir until completely coated. Spread in prepared pan; press evenly onto bottom using greased rubber spatula. Press heart candies into top of treats while still warm, evenly spacing to allow 1 heart per bar. Let cool 10 minutes. Using foil overhangs as handles, remove treats from pan. Cut into 12 bars.