Gather all ingredients such as peanut butter, marshmallows, Rice Krispies, and optional add-ins.

Melt marshmallows and peanut butter in a saucepan over low heat, stirring constantly for about 5 minutes until smooth.

Mix in Rice Krispies until fully coated, folding gently to avoid crushing the cereal.

Incorporate optional chocolate chips or nuts if desired, mixing for another minute.

Transfer the mixture into a greased baking dish, pressing down firmly but lightly.

Allow to cool at room temperature for 30 minutes or refrigerate for 15 minutes until set.

Cut into squares or rectangles and enjoy your chewy treats!