Simmer the rice in salted water for approx. 18 mins., add the spinach in the final 2 mins., drain. Mix the butter in with the rice, season, cover and keep warm.
To fry the fish
Season the fish, dust with flour, shake off the excess. Heat the clarified butter in a non-stick frying pan, fry the fish for approx. 1 1/2 mins. on each side. Keep the fish warm.
Heat the butter in the same pan. Add the onion, gherkins and capers, sauté for approx. 5 mins. Mix in the butter and parsley, heat gently. Drizzle half of the sauce over the fish, mix the rest in with the rice and serve with the fish.