Use this flavored pastry cream in our Gingerbread Trifle with Cognac Custard and Pears.
Combine yolks and sugar in the bowl of an electric mixer. Beat on medium high until mixture is pale yellow and thick, 2 to 3 minutes. Reduce speed; add flour, and beat to combine.
Meanwhile, bring milk to a boil in a medium saucepan. Slowly pour half the milk into egg mixture; beat until smooth. Pour mixture back into saucepan; set over medium heat. Whisk until mixture comes to a boil, 6 to 8 minutes. Transfer to large bowl. Stir in vanilla and cognac. Let cool. Cover surface with plastic wrap to prevent a skin from forming, and place in the refrigerator until needed or up to 3 days.