This rich, old-fashioned dessert was an immediate hit with three girlfriends I used to live with. Now my husband and I run a small church camp and our two boys consume a lot of our time and energy—as well as my peanut butter pie!
Place confectioners' sugar in a small bowl. Cut in peanut butter until crumbly. Spread half of mixture in pastry shell.
In a large saucepan, combine the sugar and cornstarch. Stir in milk until smooth. Cook and stir over medium-high heat until thickened and bubbly. Reduce heat; cook and stir 2 minutes longer. Remove from the heat. Stir a small amount of hot filling into egg yolks; return all to pan, stirring constantly. Bring to a gentle boil; cook and stir 2 minutes longer. Remove from the heat. Gently stir in butter and vanilla; set aside.
In a small bowl, beat egg whites until stiff peaks form. Spread reserved custard evenly over peanut butter mixture. Spread meringue over hot filling, sealing edges to crust. Sprinkle with reserved peanut butter mixture. Bake at 350° for 12-15 minutes or until the meringue is golden brown. Cool on a wire rack for 1 hour. Refrigerate for at least 3 hours before serving. Store leftovers in the refrigerator.