Cook the rice according to the instructions on the packet. Finely hook the parsley and set aside.
Wash the lemon, rub dry, rub the lemon peel and squeeze out the juice. Peel the onion and chop finely.
Heat the butter and sauté the onion cubes until translucent. Deglaze with fish stock and cream and let simmer for 5 - 10 minutes while stirring. Stir in half of the lemon juice and the lemon zest and season with salt, pepper, sugar and the remaining lemon juice.
Put the cooking oil in a pan and heat it up. Fry the salmon fillets on each side for about 3 minutes.
Fold the parsley into the rice. Arrange the salmon fillets on plates and serve with the parsley rice and the sauce.