Scrape the seeds from the vanilla bean and stir into the milk. Set aside. If using pure vanilla extract, stir 2 teaspoons of extract into the milk. Preheat oven to 350 degrees F.
In an ungreased 9" pie plate, combine the graham cracker crumbs and brown sugar. Mix in butter. Press the crumbs onto the bottom and up the sides the pie plate. Bake the crust for 8-10 minutes or until lightly browned. Cool on a wire rack.
In a small saucepan, combine the sugar, flour and salt. Whisk in milk until smooth. Cook and stir over medium-high heat until thickened and bubbly. Reduce heat, and cook and stir 2 minutes longer. Remove from the heat.
Spoon a small amount of hot milk mixture into egg yolks and stir. Add a couple more spoonfuls, stirring well after each addition. Return all to the pan. Bring to a gentle boil and stir constantly. Cook and stir 2 minutes longer. Remove from the heat. Pour into prepared crust.
In a small bowl, beat the egg whites, vanilla and cream of tartar with a mixer on medium speed until soft peaks form. Beat in sugar 1 tablespoon at a time, on high speed until stiff peaks form. Spread meringue over hot filling, sealing edges to crust.
Bake at 350 degrees F for 15 minutes or until golden brown. Cool on wire rack for 1 hour. Refrigerate for at least 3 hours before serving.