1. In a large bowl, beat peanut butter, softened butter, confectioners sugar and vanilla extract until smooth. Roll into 1-inch balls and place on parchment-paper-lined baking sheets. Place in freezer for 30 minutes, until firm.
2. Melt chocolate chips per package directions. Using a toothpick, dip peanut butter balls halfway into chocolate, allowing excess to drip off. Return to parchment-lined baking sheets. With a moistened finger, smooth out toothpick holes. Refrigerate to harden chocolate; keep refrigerated until serving.