To chill the tea mixture quickly, place it in a measuring cup or small bowl and nest it inside a larger bowl filled with ice. Stir the mixture occasionally to hasten the cooling. To make whipped cream, in a large metal bowl, combine 1 cup well-chilled heavy cream, 1 tsp. vanilla extract and 2 Tbs. confectioners' sugar. Using an electric mixer on medium-high speed, beat until soft peaks form.