Line a rimmed baking sheet with parchment paper and clear a flat space for it in the freezer.
Beat the peanut butter, softened butter, vanilla and salt in a large bowl until smooth and fluffy.
Add the sifted powdered sugar 1 cup at a time, mixing on low after each addition, until a soft dough forms.
Scoop 1 tablespoon portions and roll them between your palms into smooth balls. Set them on the prepared sheet.
Press a toothpick into the top center of each ball. Freeze for 30 minutes, until very firm.
Melt the chocolate chips and coconut oil in short bursts in the microwave, stirring between each, until smooth and glossy.
Dip each frozen ball about three quarters deep into the chocolate, leaving a small circle of peanut butter showing at the top.
Set the ball back on the sheet, twist the toothpick out, and smooth the little hole closed with a fingertip.
Chill the tray for 15 minutes, until the chocolate is fully set.