Make Crust: Mix crust ingredients. Reserve 2–3 tbsp for topping. Press into 9-inch pie dish and bake at 350°F (175°C) for 10 min. Let cool.
Prepare Custard: Whisk sugar and cornstarch. Add milk, yolks, and salt. Cook until thickened. Stir in vanilla. Pour into cooled crust.
Make Meringue: Beat egg whites and cream of tartar to soft peaks. Add sugar gradually. Beat to stiff peaks.
Assemble: Spread meringue over warm custard, seal edges, top with reserved crumbs.
Bake: Bake at 350°F for 10–12 minutes until golden. Cool, then refrigerate for 2+ hours.