Preheat oven to 350°.
To prepare crust, combine first 3 ingredients, and stir well with a whisk. Add melted butter; toss until moist. Reserve 2 tablespoons crumb mixture; set aside. Press the remaining mixture into bottom and up sides of a 9-inch pie plate coated with cooking spray; lightly coat crust with cooking spray. Bake at 350° for 15 minutes, and remove from oven. Reduce oven temperature to 325°.
To prepare the filling, combine 1/2 cup sugar, cornstarch, and salt in a saucepan; stir in milk. Bring the mixture to a boil over medium heat. Cook for 1 minute, stirring constantly. Gradually add the hot milk mixture to eggs, stirring constantly with a whisk. Return mixture to pan. Cook over medium heat until thick (about 2 minutes), stirring constantly. Remove from heat, and stir in 1/4 teaspoon vanilla. Pour the hot filling into prepared crust.
To prepare meringue, place the egg whites and the cream of tartar in a large bowl; beat with a mixer at high speed until foamy. Add 1/2 teaspoon vanilla, and beat well. Gradually add 1/3 cup sugar, 1 tablespoon at a time, beating until stiff peaks form. Spread meringue evenly over the hot filling, sealing to edge of crust. Sprinkle with the reserved crumb mixture. Bake at 350° for 15 minutes or until meringue is golden. Cool 1 hour on a wire rack. Chill at least 2 hours.