Heat oven to 350 degrees. Spray bottom of 9x13 in pan with cooking spray.

In medium bowl, stir cookie mix, butter, flour, lemon zest and 1 egg until crumbly dough forms. Press firmly into the pan.

Bake 15 – 18 minutes or until light golden brown (Watch this closely as the bottom of the cookies get really done if you over bake!). Cool 15 minutes. Meanwhile, in large bowl, beat cream cheese, sugar, vanilla, lemon zest and 2 eggs with electric mixer on medium speed until smooth. Spread evenly over crust in pan.

For the lemon topping, mix the sugar and cornstarch in pot over medium heat and cook for about 2 minutes. Add the water and lemon juice to the sugar mixture and stir constantly. Once the sugar is completely dissolved and the mixture begins to thicken slightly, remove from the heat. In a separate bowl, beat the two egg yolks before adding 2 Tbsp of the sugar mixture to the eggs to temper them. Then add the tempered eggs into the sugar mixture. Put mixture back on medium heat and stir constantly for 3-5 minutes. Once the mixture has thickened nicely, remove from heat and dollop over the cheesecake mixture. Use knife to pull lemon from side to side through cream cheese mixture to create the lemon swirl.

Bake 25 – 30 minutes or longer until filling is set. Refrigerate until chilled, about 2 hours.