Preheat the oven to 375°F and grease a 9” pie pan.
Mix all of the crust ingredients together and press in an even layer into the prepared pie pan.
Bake for 6 - 8 minutes.
Then remove from oven and let cool.
Cream Cheese Filling
Combine the cream cheese, sugar, sour cream, and salt in a medium saucepan and cook on very low heat, stirring constantly until the mixture starts to boil lightly.
Mix the gelatin with the water. When the gelatin has dissolved, add it to the saucepan along with vanilla and stir well. Return the mixture to a light boil and cook for 2 minutes. Remove from the heat and let it cool to lukewarm.
When the cream cheese filling is lukewarm, layer it on top of the crust and refrigerate until cooled.
Lemon Topping
Place the water, sugar, lemon juice, cornstarch, salt, and lemon zest in a saucepan over medium heat, and whisk until mixture comes to a boil. Cook for 2 minutes until thick.
Slowly pour half of the hot mixture into the beaten egg yolks, stirring constantly. When the mixture is completely blended, pour the egg mixture back into the remaining hot pudding.
Cook and stir until the pudding reaches a slow boil. Stir and let boil slowly for about 5 minutes.
Remove from the heat. Add the butter and vanilla, stir, and set aside to cool.
When the lemon mixture reaches room temperature, gently smooth it over the cream cheese mixture and chill for several hours before serving.