Place all ingredients, except whipping cream in a blender. Be careful of the fumes, they can be overwhelming.
Blend until finely grated.
In a separate bowl, beat whipping cream until soft peaks form.
Fold in 1/4 cup of the horseradish mixture.
Cover and chill for at least one hour before serving.
Store in refrigerator for up to 2 weeks.
Heating the grated horseradish mixture tones it down a bit. If you like horseradish with lots of bite, don't heat.
Store remaining horseradish mixture (without the whipping cream) in the freezer.