Combine Flour, powdered sugar, melted butter, vanilla and salt until well combined and pebbly. Then press it into an 8X8 Square baking pan. Bake at 350 for 10 minutes.
While the crust is baking, combine the eggs, sugar, lemon juice and extract OR oil in a large bowl and mix thoroughly, then set aside.
In a separate large bowl, mix softened cream cheese, sugar, vanilla and egg with a hand mixer until very smooth.
When the crust is baked, remove it from the oven and spray the sides of the pan with Pam Spray. Then pour the cheesecake layer over the crust. Then whisk the lemon mixture once more and gently pour it over the cheesecake layer. Reduce oven temperature to 325 degrees and bake 30 to 35 minutes, or until the crust is lightly golden on top.