Mix the peanut butter and butter together in a large mixing bowl.
Gradually stir in the sugar until combined well into a dough ball.
Cover with plastic wrap and refrigerate until ready to form balls (at least 15 minutes).
Shape into small balls (about 1-inch), place on a baking sheet, cover, and refrigerate for at least 20 minutes to allow to firm up again.
Melt chocolate in a microwave-safe bowl at 15 second intervals until smooth.
Dip peanut butter balls one at a time into melted chocolate, allowing excess chocolate to drip off.
Place on a parchment paper lined baking sheet, cover and refrigerate until ready to serve.