Bob Swanson, from my hometown of Appleton, Wisconsin, baked wonderful pies. I have adjusted his original recipe to reduce the fat content.
To make Crust: Set oven rack at lowest level, and preheat to 375F. Lightly oil a 9-inch glass pie plate, or coat it with nonstick cooking spray. Set aside.
Stir together flour, sugar and salt in a mixing bowl. Melt butter in a saucepan over low heat, swirling it in the pan for about 30 seconds, until light brown. Pour into a small bowl, and set aside to cool. Stir in oil.
Using a fork, slowly stir butter-oil mixture into flour until mixture is crumbly. Gradually stir in enough ice water, about 1 to 2 tablespoons, so that dough holds together. Press dough into a flattened disk.
Place 2 sheets of plastic wrap overlapping by 2 inches on work surface. Place pastry in center, and cover with 2 more overlapping sheets of plastic wrap. With a rolling pin, roll dough into a circle about 12 inches round. Remove the top sheets, and invert the dough over the prepared pie plate. Carefully peel away remaining plastic wrap. Fold edges under at rim, and crimp. Chill pastry while you prepare filling.
To make Filling: Beat together sugar and butter in a mixing bowl until well mixed. Beat in egg, egg whites, milk and vanilla until well blended. In another bowl, toss rhubarb with flour. Stir rhubarb into egg mixture. Turn filling into crust-lined pan, spreading evenly.
Bake for about 11/4 hours, or until filling is firm. Remove from oven, and let cool to room temperature before adding meringue.
To make Meringue: Position rack in center of oven, and preheat to 375F.
Beat egg whites with an electric mixer on medium speed until frothy. Add cream of tartar, and beat on high speed just until soft peaks form. While beating egg whites, gradually add sugar. Beat mixture until whites are stiff and glossy. Spread meringue over pie filling, making sure that it touches edge of crust all around.
Bake for 12 to 15 minutes, or until top is lightly browned. Let cool on a rack for 1 hour before serving.