For the crust: preheat the oven to 350ºF*. In a bowl, stir the graham cracker crumbs, sugar and salt together. Add the butter and stir to mix. Pour the crumbs into a 9-inch pie dish, and press the crumbs firmly and evenly into the bottom of the dish and up the sides. I think it is easiest to use a cup to press the crumbs firmly into the dish. Bake the crust in the oven for 7 minutes, then remove and let cool completely.

For the pie: place the cream cheese in a large bowl and beat until smooth. Add the sweetened condensed milk, lemon juice and lemon zest and continue to beat until as smooth as possible. This may take a few minutes. If desired, mix in a few drops of yellow food coloring. Pour the filling into the pie crust and smooth the top with an offset spatula. Cover the pie with plastic wrap and refrigerate for at least 2 hours.