Blend the rosemary and 300g salt together in a food processor.
Mix the flour and rosemary salt in a stand mixer, then add egg whites and 300ml water.
Knead the dough in the machine for five minutes until it comes together.
Wrap the dough in cling film and let it rest for two hours.
Preheat the oven to 150°C.
Roll out the dough to 1cm thickness and cut into four equal rectangles.
Blend the garlic cloves into a paste with 50ml water.
Brush the garlic purée over the lamb shanks.
Wrap each shank in dough, ensuring the bone sticks out of the top.
Bake in a roasting tray for 4.5 hours and rest for 30 minutes after baking.
Boil all pickling liquor ingredients except the cabbage in a saucepan.
Remove from heat and let the liquor infuse for 30 minutes.
Strain the liquor into a bowl and let it cool completely.
Place the cabbage in the cooled liquor to pickle for at least one hour.
Mix the onions and chilli with sea salt and set aside for 20 minutes.
Combine drained pickling cabbage with the onion salad, adding chives and rapeseed oil.
Blend mayonnaise ingredients while slowly adding vegetable oil until thickened.
Break the salt crust and serve lamb with cabbage salad, mayonnaise, and nasturtium leaves.