Clean and salt the fish fillets, please do not acidify and then halve lengthways, brush generously with the herb butter. Season with pepper and roll up lengthways, fix with toothpicks.
Turn in flour and slowly fry all over in a pan in a mixture of rapeseed oil and the rest of the herb butter.
Clean the spring onions and cut each one twice. Stew in a little oil in a second pan and serve with the fish.