Combine ingredients: In a large bowl, cream together the softened butter and peanut butter until smooth.
Add powdered sugar: Gradually add the powdered sugar, mixing until well combined.
Stir in crumbs: Stir in the graham cracker crumbs (or vanilla wafer crumbs) until the mixture is evenly distributed.
Form the balls: Roll the mixture into 1-inch balls.
Chill: Place the peanut butter balls on a baking sheet lined with parchment paper or wax paper. Refrigerate for at least 2 hours, or preferably overnight, to allow them to firm up.
Melt chocolate: While the balls are chilling, melt the chocolate chips in a double boiler or microwave (in 30-second intervals, stirring in between) until smooth.
Dip the balls: Dip each chilled peanut butter ball into the melted chocolate, coating it completely. You can use a fork or toothpick to help with dipping.
Add toppings (optional): Before the chocolate sets, you can add sprinkles, chopped nuts, or other toppings.
Set: Place the chocolate-covered peanut butter balls back on the prepared baking sheet and refrigerate for another 30 minutes to allow the chocolate to set completely.
Serve: Serve the peanut butter balls chilled.