Preheat oven to 350°F (175°C).
Mix graham cracker crumbs, sugar, and melted butter. Press into a pie dish to form the crust.
Bake crust for 10 minutes. Let cool.
In a saucepan, combine milk, sugar, and cornstarch. Cook over medium heat until thickened.
Temper the egg yolks by adding a small amount of the hot mixture to them, then return to the saucepan. Cook for another 2 minutes.
Remove from heat and stir in vanilla extract. Pour custard into the cooled crust.
In a clean bowl, beat egg whites and cream of tartar until soft peaks form. Gradually add sugar and beat until stiff peaks form.
Spread meringue over the custard, sealing the edges.
Bake for 10-12 minutes, or until meringue is golden brown. Let cool before serving.