Rub the fish fillets with salt and pepper. Finely chop the sunflower seeds and mix with the breadcrumbs in a plate.
Whisk the egg with a little salt in a second plate.
Roughly chop the parsley and sauté in the heated butter.
Pour in the fish stock and cream, season with salt and pepper. Let everything simmer for 5 to 6 minutes, then puree with the electric blender. Keep warm.
Pull the fillets through the egg and turn them in the breading.
Heat the oil and butter in a pan and fry the fish fillets until golden brown on both sides. Serve with the parsley sauce.