Prepare Your Tray: Line a large baking sheet or tray with parchment paper. Make sure it will fit in your freezer!

Mix the Peanut Butter Base: In a large mixing bowl, combine the smooth peanut butter, room temperature unsalted butter, vanilla extract, and salt. Using an electric hand mixer (or a stand mixer with the paddle attachment), beat on a medium speed until everything is well combined and creamy.

Add the Icing Sugar: Gradually add the sifted icing sugar to the bowl, about a third at a time, mixing on a low speed until it's incorporated. The mixture will become quite thick and stiff, resembling a dough.

Roll the Balls: Scoop out portions of the mixture (about 1 tablespoon each) and roll them between your palms to form smooth balls, approximately 2-3 cm in diameter. Place the balls onto the prepared baking sheet.

Chill Firmly: Once all the balls are rolled, insert a cocktail stick into the top of each one. Place the entire tray into the freezer for at least 30 minutes, or into the refrigerator for an hour. The balls should be very firm to the touch. What works best for me is the freezer, as it makes the dipping process much cleaner.

Melt the Chocolate: Just before the chilling time is up, melt the chocolate. Place the chopped dark chocolate and coconut oil in a microwave-safe bowl. Microwave in 30-second bursts, stirring well between each one, until the chocolate is almost completely melted. Stir until smooth and glossy. Alternatively, melt it in a heatproof bowl set over a saucepan of gently simmering water (a bain-marie). The coconut oil helps create a smoother, shinier coating.

Dip the Buckeyes: Working quickly, take the tray of peanut butter balls from the freezer. Hold each ball by its cocktail stick and dip it into the melted chocolate, leaving a small circle at the top uncovered (this is the classic "Buckeye" look).

Let the Excess Drip: Allow any excess chocolate to drip back into the bowl before placing the dipped Buckeye back onto the parchment-lined baking sheet.

Set and Finish: Once all the balls are dipped, place the tray in the refrigerator for about 15-20 minutes, or until the chocolate is completely set. Once firm, you can gently twist and remove the cocktail sticks. Use your fingertip to smooth over the small hole left behind.