Wash the beetroots then wrap them in aluminium foil and roast in oven at 200C for 40 minutes. Allow them to cool, then peel and chop them into small dice.
Chop the onions and sauté them on butter with some salt. Add the spices and ¾ of the beetroot and then fill it up with the must. Blend the whole lot and if necessary sieve it. Let it rest in the fridge for a night.
Whip the double cream into a stiff foam and then add the horseradish. Caramelize the rest of the beetroot and the grapes with some honey.
Serve in plates, add some double cream on top, sprinkle it with dill and finally add the caramelized grapes and beetroot.