Prepare a large baking sheet with parchment paper.
Add peanut butter and melted butter to a large mixing bowl, mix until creamy.
Add powdered sugar to peanut butter mixture in batches, mixing well.
Gently fold in Rice Krispies cereal into mixture.
Using Tablespoon-sized cookie scoop, scoop mixture and roll into balls.
Place the balls onto prepared sheet pan, then refrigerate for at least 30 minutes.
Melt chocolate wafers or chips in a heat-safe bowl in the microwave for 30 seconds, then in 15-minute increments, stirring in between, until smooth. Add the optional shortening or coconut oil to the chocolate to help make it smooth.
Poor melted chocolate into a glass jar.
Using toothpicks/skewer or a fork, dip each ball into melted chocolate until coated, them place back onto prepared sheet pan.
Refrigerate for an additional 20 minutes to set coating, then serve.