In a large bowl, mix together peanut butter, butter, and vanilla until completely smooth.
One cup at a time, add powdered sugar. Start by mixing with a spoon and then mix with hands to form a thick dough. For the last cup of powdered sugar, be sure to add it slowly one heaping spoonful at a time until you reach your desired consistency.
Shape tablespoon sized balls and roll them smooth in between your hands. Set on parchment lined baking sheet. Refrigerate for two hours for freeze for at least 15 minutes.
In a medium sized bowl, combine chocolate and remaining butter and microwave at half power in one minute increments, stirring each time, until everything has melted and is completely smooth.
Dip each peanut butter ball in the chocolate. You may use one or two toothpicks to poke into the peanut butter ball to make it easier to dip into the chocolate. If you do, simply smooth over any holes the toothpick leaves in the ball. Return the dipped peanut butter balls back to the parchment lined sheet and allow to set.
Store in an airtight container in the refrigerator or freeze until you devour them.
Yields 40 Buckeye Balls, nutritional information based on one ball