Pour the cereal into a large mixing bowl and set aside.

Over medium heat, add the butter to a large saucepan and melt.

Add the large marshmallows to the pot and stir to combine with the butter. Continue to stir until the marshmallows have melted and are smooth.

Add the mini marshmallows to the pot and stir until they melt but are still visible.

Turn off the heat, stir in the vanilla and peanut butter.

Pour the marshmallow mixture over the cereal and stir to combine.

Pour the cereal mixture into a 9x9 inch baking dish coated with cooking spray.

Press the mixture into an even layer with your hands coated in butter or cooking spray to prevent sticking.

Allow the mixture to cool to room temperature.

Melt the chocolate in a microwave safe bowl at 30 second increments stirring between each interval until smooth.

Transfer the chocolate to a plastic bag and snip off the corner of the bag. Drizzle the chocolate over the treats and sprinkle with chopped peanuts.

Allow the chocolate to set.

Cut the Krispie treats into squares and serve immediately or transfer to an airtight container and store at room temperature for up to 5 days.