Cream butter, peanut butter, and vanilla together; add confectioner’s sugar. Roll into one-inch balls. Place on waxed paper-lined cookie sheet; chill thoroughly.
Melt chocolate chips and vegetable oil together in top of double boiler. Keeping chocolate mixture in double boiler over low heat, use a toothpick to dip each ball in chocolate, covering about 3/4 of each. Return buckeyes to cookie sheet to cool.
Yield: Approximately 30 balls.