1.2 kg(about 6) beetroot2 tspyellow mustard seeds½ tspcumin seeds125 ml (½ cup) cider vinegar1 tbspcaster sugar120 gm (½ cup)sour cream1 tbspfinely grated fresh horseradish, plus extra for scattering (see note)½ cup(loosely packed) dill sprigs
Place beetroot in a large saucepan, cover with cold, salted water, bring to the boil, then reduce heat to medium and simmer until beetroot is tender (about 1 hour). Drain, cool slightly, then peel and thickly slice.
Meanwhile, combine mustard seeds and cumin in a mortar and, using a pestle, coarsely crush, then combine in a small bowl with vinegar and sugar and stir until sugar dissolves. Pour over beetroot, season to taste with sea salt and freshly ground black pepper and stand for 30 minutes.
In a small bowl, whisk together sour cream and horseradish and season to taste. Arrange beetroot in a serving dish, scatter dill and extra horseradish over and serve with horseradish cream to the side.
Note If fresh horseradish is unavailable, substitute bottled horseradish.