Crust: combine graham crackers and sugar in bowl. Stir in the butter. Press mixture into the bottom and up the sides of a well-greased 7 inch pie dish. Bake at 350 degrees F. for 8 minutes. Meanwhile, prepare filling.

Whisk the egg yolks together in a bowl and set aside. In a medium saucepan that is not yet set over heat, stir together the brown sugar, flour, and salt. Now that everything is assembled, stop and prepare the meringue. It can sit while you do the next step.

Combine the egg whites and the salt and mix on high speed with hand mixer until soft peaks form. Add the sugar 2 tablespoons at a time until the sugar is dissolved and stiff peaks form. Set aside while you finish making the filling.

Warm the milk in the microwave for about a minute. Set the saucepan with the brown sugar mixture over medium heat and whisk in the milk. Continue to whisk over medium heat until mixture begins to simmer. Pour about half of the milk mixture into the egg yolks, whisking constantly, then add the egg yolk mixture back to the saucepan and continue whisking and stirring over medium heat until mixture thickens and bubbles. Whisk and stir for another 2 minutes while the mixture bubbles and cooks. This whole process doesn't take long at all -- especially if you use warm milk and a metal saucepan.

Remove from heat and whisk in the butter and vanilla. Pour into the prepared pie crust and quickly top with the meringue, sealing the edges. Bake the pie for 10 minutes at 350 degrees F. Let cool at room temperature for an hour, then transfer to the refrigerator and chill for 4 hours or more.