The bourbon gives an extra note of richness to this pie.
Cream butter and brown sugar in a large mixer bowl. Add eggs, corn syrup, corn starch, bourbon and vanilla. Beat until well mixed.
Portion 4 ounces pecans into each pie crust. Evenly divide filling into pie crusts. Top each pie with 4 ounces pecans.
Bake at 350ºF for 55 to 65 minutes or until center appears barely set. Cool to room temperature on wire rack. Refrigerate until ready to serve.