Cut cookie dough in half. Let one portion stand at room temperature for 5-10 minutes to soften (return other half to the refrigerator for another use). Press dough onto the bottom and up the sides of an ungreased 9" pie plate. Bake at 375* for 11-12 minutes or until lightly browned. Cool on a wire rack.
In a large saucepan, combine the sugar, cornstarch, and salt. Stir in milk until smooth. Cook and stir over medium-high heat until thickened and bubbly. Reduce heat; cook and stir 2 minutes longer. Remove from heat. Stir in a small amount of hot filling into the egg yolks; return all to pan, stirring constantly. Bring to a gentle boil; cook and stir 2 minutes longer. Remove from heat; stir in butter and 1 teaspoon of vanilla.
Spread 1 cup filling into prepared crust. Slice bananas; arrange over the filling. Pour remaining filling over bananas. Refrigerate for 2 hours or until set.
In a chilled large mixing bowl, beat cream until it begins to thicken. Add powdered sugar, and remaining vanilla; beat until stiff peaks form. Spread over pie. Refrigerate for 1 hour or until chilled. Refrigerate left overs. Enjoy!