Preheat the oven to 60°C, warm the plates. Season the fish fillets. Heat the clarified butter in a non-stick frying pan. Fry the fish fillets in batches for approx. 1 min. on each side, remove from the pan, keep warm in the oven.
Heat the butter and capers in the same pan until the butter foams and smells nutty. Add the lemon zest, lemon juice and stock, bring to the boil, reduce the heat. Mix the butter and flour, add with the sugar while stirring, simmer for approx. 5 mins., season.
Cook the rice in boiling salted water until just soft, drain. Heat the oil in the same pan. Sauté the garlic for approx. 5 mins. until it turns light brown. Add the radish and cook briefly. Add the rice and parsley, cook for approx. 5 mins. while stirring. Plate up the lemon sole fillets with the sauce and the radish rice.