It is important to add flavorings to Pastry Cream while it is still warm. If you plan to make both the Citrus Tart and the Mocha Teacup Parfaits, double this recipe, then divide the Pastry Cream into two portions and flavor accordingly.
1/2 cup sugar
1/8 teaspoon salt
1/4 cup cornstarch
4 large egg yolks, lightly beaten
2 cups whole milk
1 tablespoon butter
1 teaspoon vanilla extract
Combine first three ingredients in a heavy saucepan; gradually whisk in yolks and milk. Bring to a boil over medium heat, whisking constantly. Boil 1 minute or until thickened. Stir in butter and flavorings.