Roll dough into a 12-inch circle; fit into a 9-inch pie plate coated with cooking spray. Fold edges under, and flute. Bake piecrust according to package directions. Cool completely on a wire rack.
Combine sugar, 2 1/2 teaspoons rind, and the next 4 ingredients (through eggs) in a large bowl, stirring well. Combine milk and cheese in a medium, heavy saucepan over medium-high heat; cook until mixture reaches 180° or until tiny bubbles form around edge (do not boil). Gradually add the hot milk mixture to sugar mixture, stirring constantly with a whisk. Return milk mixture to pan, and cook over medium heat 10 minutes or until thick and bubbly, stirring constantly. Remove from heat; stir in butter.
Place pan in a large ice-filled bowl for 10 minutes or until the mixture cools to room temperature, stirring occasionally. Spoon filling into prepared crust, and cover surface of filling with plastic wrap. Chill for 3 hours or until set, and remove plastic wrap. Spread the whipped topping evenly over chilled pie, and sprinkle with remaining 1/2 teaspoon lemon rind.