Soak the gelatine in cold water for about 10 minutes. Season the beetroot juice with vinegar, salt and pepper. Whip the cream until stiff.
Dissolve the gelatine dripping wet over a mild heat, stir into the beetroot juice, chill. When the liquid begins to gel (approx. 1/2 hour), fold in the whipped cream. Chill for a few hours and then cut off the cams with wet spoons or fill them into appropriate molds beforehand.
As a greeting from the kitchen: Arrange the plates with a frisee lettuce leaf and pour the balsamic reduction over the beetroot foam.