Now is the time to add the whipped cream to the pastry cream. First, whip the heavy whipping cream. To do so, first put a bowl and the beaters of the electric mixer in the freezer for about 15 minutes. This will make it easier to whip the cream. Then, pour the heavy whipping cream in the cold bowl and whip it with the electric hand mixer, first on low speed, and then gradually increasing speed. Please be patient, this might take some time.