Heat oven to 350°F. Bring 1 crust to room temperature as directed on box; slowly and gently unroll crust. In ungreased 9-inch glass pie plate, place crust, pressing firmly against bottom and side. Trim any overhang; crimp edge, using the tines of a fork. Place in refrigerator while preparing filling.
In deep bowl, stir together butter, sugar and cocoa until blended. Add eggs and vanilla. Beat, using whisk, until mixture is blended and thickens. Stir in cornmeal just until combined; pour into crust.
Bake 35 to 45 minutes or until pie is set and top puffs up and forms hard crust. Cool completely. Serve at room temperature with a dollop of whipped cream.