Cook the mussels in the white wine, onion, garlic and thyme until they open.
Strain and reserve the juice.
To make the buttermilk foam
Warm the stock and cream.
Bloom the gelatine and dissolve into the mix.
Add the buttermilk, season and pour into a siphon gun and charge twice. Keep warm.
To make the oyster mayonnaise
Place the four oysters with their juices in a plastic container.
With the aid of blender, emulsify the oil into the oyster. Season to taste.
Cut the leeks in three. Poach in simmering water until soft. Place on a ripped grill and char.
Pan fry the scallops in hot oil until the one side is brown and crispy.
Turn over in the pan and add some butter.
Reduce heat and baste the scallops until they are cooked. Ensure the scallop is still translucent in the centre.
Place the grilled leaks on the plate. Add a little oyster mayonnaise. Arrange two scallops around the leeks. Warm the mussels and dress around the leek. Finish with the buttermilk sauce.