Line a baking sheet with parchment paper.
In a stand mixer fitted with the paddle attachment on medium-high speed, cream 4 tablespoons of the butter, the peanut butter, and powdered sugar for 1 minute, until smooth.
In a 5-quart stock pot over medium heat, melt the remaining 3 tablespoons of butter. Add the marshmallows and vanilla and cook, stirring, until the marshmallows have melted. Add the peanut butter mixture and stir continually until the mixture is smooth. Add the cereal and stir until combined.
Form the mixture into 1 1/2-inch balls and place them on the prepared baking sheet. Refrigerate them for about 10 minutes.
Meanwhile, follow the directions on the chocolate bark to melt it. Stir until smooth.
Using a fork, place a peanut butter ball in the melted chocolate and coat it fully, then set it back on the baking sheet. Repeat until all the balls have been dipped in chocolate coating.
Refrigerate again until the coating has hardened, about 20 minutes.
When cool, transfer the balls to an airtight container and refrigerate for up to 5 days. |