Preheat the oven to 180°C.
Heat a large ovenproof frying pan and add the butter and olive oil.
Season chicken and fry skin-side down for 4 minutes until golden.
Turn chicken over and roast in oven for 15 minutes until cooked through.
Fry garlic and shallots in a small pan with olive oil until tender.
Mix vinegar, extra virgin olive oil, and herbs, then pour over the beetroot.
Boil cauliflower for 5 minutes, then refresh in iced water and drain.
Whisk horseradish and lemon juice in a bowl, then fold in whipped cream.
Stir the drained cauliflower into the horseradish mixture.
Serve chicken with portions of the beetroot and cauliflower mixtures.