Boil 3 litres of water with brine ingredients for 10 minutes then cool.
Submerge trotters in brine and refrigerate for 24 hours.
Drain trotters, cover with fresh water and bouquet garni, and simmer for 3 hours.
Preheat the oven to 160°C.
Braise ham hock on vegetables with wine in a sealed casserole for 3.5 hours.
Cool meats, shred trotter and hock meat, and save trotter skins.
Sweat shallots in oil, then mix with parsley, shredded meats, fat, and mustard.
Roll meat mixture inside trotter skins using cling film and chill overnight.
Whisk mustard, sugar, vinegar, spices, milk, and oil into a thick salad cream.
Grate beetroot, salt for 30 minutes, rinse, and cook with onions, vinegar, wine, and horseradish.
Preheat the oven to 180°C.
Roast whole beetroots in a foil parcel with thyme and garlic for 35 minutes.
Slice chilled meat rolls, coat in flour, egg, and mustard-breadcrumbs, and shallow-fry until golden.
Serve crubeens with beetroot, dressed salad leaves, and salad cream.