Step 1

Coat an 8-inch square baking dish with cooking spray. In a medium bowl, combine graham cracker crumbs, sugar, and butter; mix well. Press crumb mixture firmly into prepared baking dish and refrigerate until ready to fill.

Step 2

In a large bowl, beat cream cheese and condensed milk until smooth. Beat in lemon juice and lemon zest. Stir in whipped topping just until mixed. Pour into graham cracker crust.

Step 3

Refrigerate 6 hours, or until filling is firm. Slice into 2-inch squares and serve.