In large saucepan melt butter over low heat.
Add marshmallows and stir until completely melted.
Remove from heat.
Stir in vanilla.
Add Kellogg's® Rice Krispies® cereal.
Stir until well coated.
Using buttered spatula, press into a 3 ½ L OR 13" x 9" buttered pan.
Cool.
Cut into bars.
