In a bowl, combine the flour, powdered sugar, and salt. Then, mix in the softened butter until the mixture resembles wet sand. Press this mixture into the bottom of a greased 9x9 inch baking pan.

In a large mixing bowl, beat together the softened cream cheese and sweetened condensed milk until smooth. Add the egg yolks, whole eggs, vanilla extract, lemon zest, and lemon juice, mixing until everything is well combined and creamy.

Pour the cream cheese mixture over the crust. Bake in a preheated oven at 325°F (165°C) for about 25-30 minutes, or until the filling is set but still slightly jiggly in the center.

Once baked, allow the bars to cool to room temperature, then refrigerate for at least 2 hours to fully set.