This stuff is like heaven in a bowl! The best way to make this fraiche, is to place the cream mixture into a larger bowl with ice, then beat the cream... the trick is to have your whipping cream and sour cream VERY cold. You can place it in the freezer for about 5 minutes until really cold, just watch it does not freeze. Do not use low-fat or fat-free sour cream, only regular full-fat for this. This takes no time to make on a heavy-duty stand mixer fitted with a whisk attachment, if you are using a hand mixer then just be patient, it will take several minutes to achieve the right consistency.