- Heat up the oil and butter in a wok or large pan over medium heat. Sauté leek and garlic for about 5 minutes or until vegetables have softened.
- Deglaze with the wine, cook for a minute then add the blue cheese and stir until completely melted. Stir through the cream, bring to a boil then toss the mussels through. Stick on the lid and cook for about 5 minutes, shaking the pan occasionally until the mussels have opened up.
- Remove mussels with a slotted spoon into serving bowls (discard any unopened mussels). Cook sauce until reduced by a third and check for seasonings (though it should be salty enough from the cheese and brine). Spoon sauce over mussels, garnish with herbs and serve hot with crusty bread.