Combine cream cheese, white sugar and powdered sugar into medium mixing bowl and beat on medium until creamy (about 1 minute).
Add egg yolk, vanilla and lemon zest and beat again just fully combined (about 1 minute).
Cover bowl with plastic wrap and refrigerate for two hours.
for crust
Combine graham crackers, salt, egg white and softened butter to large mixing bowl and stir until combined. Add flour gradually, stirring as you add it in.
Once dough is formed, mold all dough into one giant ball. Place dough ball back into mixing bowl, cover mixing bowl with plastic wrap and refrigerate for one hour.
for cookies
From dough ball, remove amount the size of a golf ball and roll into a ball in your hands. Place it onto a greased baking sheet, and slowly work a well into the middle of the dough. Make the bottom of the cookie relatively thin, and stretch the cookie so it is about three inches in diameter.
Fill the well in the middle with one large spoonful of filling, and smooth filling so it coats entire inside of cookie but has a smooth, flat top equal with top of cookie sides.
Repeat for remainder of dough, and put into oven at 350 degrees for 12-15 minutes until filling is set in the middle.
Remove, let cool for 2 minutes on baking sheet, then transfer to cooling rack for five minutes.