• 100 g (3½ oz) bone marrow
• 1 savoy cabbage, outer leaves removed, cut into 16 wedges
• 100 g (3½ oz) unsalted butter
• olive oil, for frying
• 1 pomelo, peeled, segmented

Cabbage Powder

• 300 g (10½ oz) cavolo nero leaves

Mussel Butter

• 300 g (10½ oz) unsalted butter, at room temperature, plus 1 tablespoon extra
• 3 French shallots, peeled, finely chopped
• 1 garlic clove, finely chopped
• 6 g (⅛ oz/½ cup) parsley
• 1 kg (2 lb 4 oz) mussels, scrubbed, beards removed
• 100 ml (3½ fl oz) dry white wine
• ½ lemon, juice

Lemon Purée

• 10 Meyer lemons
• 100 g (3½ oz) caster (superfine) sugar
• 50 g (1¾ oz) unsalted butter, diced
• 100 g (3½ oz) beurre noisette (browned butter)

Soak the bone marrow in iced water, leaving overnight to remove any blood. Slice into 10 g (¼ oz) slices and set aside.

To make the cabbage powder, blanch the cavolo nero in boiling water for 30 seconds. Refresh in iced water then dry on a tea towel (dish towel). Place the leaves on a baking tray lined with baking paper and dry overnight in an oven at 55°C (130°F) or use a dehydrator. Crumble the dried leaves to a fine powder in a food processor and set aside until ready to serve.

To make the mussel butter, heat a frying pan over medium–high heat and sauté the shallot, garlic and parsley in the extra tablespoon of butter. Add the mussels and white wine and continue to cook until the mussels open. Remove from the heat and remove the mussels from the shells. Reserve 16 mussels for later use, cover and store in the refrigerator. Strain the cooking liquid through a sieve lined with muslin (cheesecloth) into a clean saucepan. Place over low heat and reduce by half or until a thick syrup-like consistency is achieved. Reserve 300 ml (10½ fl oz). From the remaining mussels, remove the stomachs and chop the meat very finely. Combine with the room temperature butter, lemon juice and remaining strained mussel juice in a bowl and season with black pepper. Turn out the mixture onto a flat surface lined with plastic wrap and roll the butter mixture into a log. Wrap in the plastic wrap, seal at the ends and store in the refrigerator until ready to serve.

To make the lemon purée, put a saucepan of water over medium heat, immediately add the lemons and blanch from a cold water start. Repeat the process twice more. Cut the lemons in half and remove the seeds. Cover the base of a large saucepan with the sugar and diced butter. Put the lemon halves over the sugar mixture and cook over medium-low heat until slightly golden in colour. While still warm, blend in a high-speed blender, adding the beurre noisette and warm water as needed. Reserve the purée until ready to plate.

Heat the reserved mussel juice in a saucepan over medium heat. Add the 100 g (3½ oz) butter, cook until melted and use a stick blender on high speed to make a mussel emulsion.