Choc Chip Peanut Butter Fudge

Combine the sugar, milk and corn syrup in a heavy 3-quart saucepan and
bring to a boil, stirring constantly, until the mixture boils.
Continue boiling without stirring to the soft-ball stage (243 degrees
F on the candy thermometer). Remove from the heat. Add the butter
without stirring and cool to lukewarm, 110 degrees F. Add the vanilla
and peanut butter then beat until the mixture begins to thicken and
lose its gloss. (Watch carefully as this fudge has a short beating
time.) Quickly add the chocolate pieces and turn into a 8 X 8 X
2-inch pan. While warm, mark into squares. Cool until firm then cut
as marked. Makes about 3 dozen squares. Yield: 12 serving