In large bowl melt butter in microwave just until melted. Add marshmallows, stir to coat marshmallows with the melted butter. Continue to cook in microwave until melted, stir occasionally. This should only take a couple of minutes.
Remove from microwave and stir in vanilla.
Combine together with Rice Krispies.
Pour into buttered pan and press mixture firmly with buttered hands.
Place in refrigerator to chill.
In saucepan add caramels and water. Cook on low heat, stirring constantly until caramels are melted. Do not burn the mixture!
Remove from heat, stir in 1/2 cup peanut butter.
Pour over Rice Krispies, and spread evenly.
Place back into refrigerator to firm up a bit.
In saucepan over low heat, melt chocolate.
Once chocolate is melted remove from heat and stir in 1/4 cup peanut butter. Combine well.
Pour chocolate over caramel layer spreading to edges in even layer.
Refrigerate for 1 hour or until chocolate is firm.
Cut into squares. (cuts best if allowed to sit at room temperature for at least 1/2 hour).
Bars are best eaten at room temperature or only slightly chilled. If caramel is too hard let warm to room temperature before serving.