• Combine sugar, flour, cornstarch and salt in the top of double boiler. Mix with wooden spoon. Blend in milk gradually, then add egg yolks. Add butter.
• Place over rapidly boiling water so pan is touching water. Cook until thick and smooth, about 7 minutes, stirring constantly. Scrape down sides of pan frequently. Remove from heat. Add vanilla. Stir until smooth and blended, scraping sides of pan well.
• Poor hot filling into pie shell. Quantities may be doubled. Chill before serving.

Variations:

• Banana Cream Pie: Place sliced bananas in the bottom of pie shell. Cool filling slightly before pouring over bananas.
• Chocolate Cream Pie: Melt 1 1/2 squares unsweetened chocolate in milk in top of double boiler. Set aside to cool. Then proceed as directed using chocolate milk mixture and increasing sugar from 1/2 to 3/4 cup.
• Butterscotch Cream Pie: Substitute 3/4 cup brown sugar for granulated sugar and increase butter to 2 Tablespoons.
• Black Bottom Pie: Add 2 teaspoons unflavored gelatin to dry ingredients. Cook filling as directed. Add 1/2 cup hot filling to 1/2 cup semisweet chocolate pieces; stir until they melt the mixture is smooth. Spread chocolate mixture in the bottom of pie shell. Cover and set remaining filling aside. Add 1/4 teaspoon salt to 3 egg whites; beat until frothy. Gradually add 3 Tablespoons sugar, beating until stiff peaks form. With beater, beat half of this meringue into cream filling mixture until mixture is smooth. Fold remaining half of meringue into mixture. Spread on chocolate layer in pie shell. Chill pie several hours before serving.
• Cherry Cream Pie: Add 2 teaspoons unflavored gelatin to dry ingredients and cook filling as directed. Remove from heat; cover and set aside. Add 1/4 teaspoon salt to 3 egg whites; beat until frothy. Gradually add 3 Tablespoons sugar, beating until stiff peaks form. Beat half of this meringue into cream filling mixture until mixture is smooth. Fold remaining half of meringue into mixture. Spread 1 cup canned or homemade cherry pie filling on top of pie shell. Cover with cream filling. Chill before serving.
• Strawberry Sponge Cream Pie: Drain one 10-ounce package partially thawed frozen strawberries. If necessary, add water to make 1/2 cup juice. Combine 2 Tablespoons cornstarch and 1 Tablespoon sugar in small saucepan; slowly add juice, stirring to make a smooth paste. Cook over low heat, stirring constantly until mixture is thick and clear. Remove from heat and stir in strawberries. Set aside. Prepare filling for Vanilla Cream Pie, reducing flour to 2 Tablespoons and egg yolks to 2. Pour into pie shell. Bead egg whites at high speed until frothy. Gradually add 3 Tablespoons sugar, beating at high speed until very stiff peaks form. Fold thickened fruit into egg whites. Spread evenly on hot cream filling, sealing to crust all around. Bake in moderate over (350 degrees) about 30 minutes. Cool before serving.
• Raspberry Cream Pie: Follow directions for Strawberry Sponge Cream Pie, substituting raspberries for strawberries.
• Blueberry Cream Pie: Follow directions for Strawberry Sponge Cream Pie, substituting blueberries for strawberries. Add 1 teaspoon lemon juice to berries.