To make these cookies, start by lining a large baking sheet with parchment paper and setting it aside.
In a large bowl, mix together the puffed rice cereal, marshmallows, and mini chocolate chips if using.
Now, melt the chocolate. In a separate bowl, add the white chocolate chips and coconut oil.
Microwave in 2-3 30-second increments, stirring between each, until the mixture is smooth and fully melted.
Once melted, add the peanut butter and vanilla directly into the warm chocolate mixture. Stir until smooth, creamy, and completely combined.
Pour the peanut butter-chocolate mixture over the cereal mixture and fold gently until everything is well coated.
Scoop 2-3 tablespoons of the mixture onto the prepared baking sheet. Depending on how big or small you make them, you'll end up with anywhere between 18-24 cookies.
Finally, place teh baking sheet in the refrigerator for about 30 minutes. Once firm, enjoy immediately or transfer them to an airtight container for storage in the fridge for 1 week or the freezer for 2 months.