01 - Preheat oven to 350°F. Prepare a 9"x13" baking dish.
02 - In a medium bowl, combine flour, butter, and powdered sugar. Mix until crumbly, then press firmly into the bottom of the baking dish.
03 - Bake for 18–20 minutes until lightly golden. Remove from oven and let cool completely.
04 - Beat softened cream cheese and powdered sugar together until smooth and creamy. Fold in 1 cup whipped topping until well combined. Spread evenly over the cooled crust.
05 - In a large bowl, whisk together instant lemon pudding mixes, cold milk, and lemon zest (if using) for 2 minutes until thickened. Spread over the cream cheese layer.
06 - Spread remaining 2 cups whipped topping gently over the lemon pudding layer.
07 - Refrigerate for at least 2 hours, or until fully set.
08 - Garnish with lemon slices or zest before serving, if desired. Cut into 12 squares and serve chilled.