Add the peanut butter and softened butter to the bowl of a stand mixer fitted with the paddle attachment (or to a large bowl, if using a hand mixer). 

Beat on medium speed until the mixture is smooth and combined. Add the vanilla and mix again to combine. 

With the mixer on low speed, slowly add the powdered sugar a little at a time. 

Once all of the powdered sugar has been incorporated, add the graham cracker crumbs and mix to combine. 

Line a baking sheet with parchment or wax paper. Scoop out 15 portions (about 1 tablespoon each) and roll them into the lined baking sheet. 

Place the peanut butter balls in the freezer for 20 minutes. 

When the peanut butter balls are chilled, add the chocolate chips and chocolate bark to a medium-sized heatproof bowl and microwave for 1 minute. Stir to combine. If the chocolate is not fully melted, microwave it for an additional 30 seconds. 

(Optional) For a shiny chocolate coating, add 1 tablespoon of coconut oil. 

One at a time, dip the peanut butter balls into the melted chocolate and place them back on the lined baking sheet. Garnish with a sprinkle of graham cracker crumbs or flakey sea salt, if desired — just make sure to add it before the chocolate is fully set so it sticks! 

Place the peanut butter balls back into the fridge to set for 10 minutes. Then enjoy immediately or store in an airtight container in the fridge for up to 3 days.