Lemon Refrigerator Bites

1 1/C cups graham cracker crumbs
1/4 C sugar
1/2 C (1 stick) butter, melted
1-8 oz pkg cream cheese, softened
1-14 oz can sweetened condensed milk
1/2 C fresh lemon juice
1 tsp finely grated lemon zest
2 C frozen whipped topping, thawed

Coat an eight-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. 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. Refrigerate for six hours or until filling is firm. Slice into two-inch squares and serve.