Peanut butter rice krispie treats are a tasty and easy-to-make dessert for a kids' birthday party. Start by melting butter and peanut butter in a large saucepan over low heat. Add marshmallows and stir until melted and well combined. Remove from heat and stir in rice krispies cereal until evenly coated. Press the mixture into a greased baking dish and let it cool completely. Cut into squares or use cookie cutters to create fun shapes. These chewy and peanut buttery treats will be a hit with kids of all ages.