Peanut Butter Pie

1 (9 in) pie shell, baked
1 cup confectioners' sugar
1/2 cup peanut butter
2 cups milk
2/3 cup white sugar
1/4 tsp salt
1/2 tsp vanilla extract
4 tablespoons cornstarch
3 eggs, separated
1/2 tsp cream of tartar
6 tablespoons white sugar

1. Mix confectioners' sugar and peanut butter until mixture has a crumbly texture. Sprinkle half over the bottom of the shell.
2. In he top of double boiler, combine milk, 2/3 cup sugar, salt, vanilla, cornstarch, and egg yolks. Cook over medium-low heat until thick. Pour filling into crust.
3. Beat egg whites until foamy. Add cream of tartar, and continue beating. Gradually add 6 tablespoons sugar, and continue beating until stiff peaks form. Spread over the top of the pie. Sprinkle with remaining peanut butter mixture.
4. Bake at 325 degrees for 30 minutes