Separate the 4 eggs and bring them to room temperature. Have the whites in a metal mixing bowl (the one you’ll use for the meringue) and the yolks in any large mixing bowl. Measure out all of the other ingredients and assemble.Preheat the oven to 350 degrees F. and grease a 9 inch glass pie dish.Prepare the crust first.
Combine graham crackers and sugar in bowl. Stir in the butter. Press mixture into the pie dish and bake at 350 degrees F. for 8 minutes.When crust is ready, begin preparing the 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 so you’ll have it ready to put over the hot filling.
Combine the egg whites (which should already be in the metal bowl) 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 it aside and proceed with the filling.Warm the milk in the microwave for 1 ½ minutes. 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, then add the egg yolk mixture 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.
