Brine the pork knuckles (1 l water, 6 tablespoon salt, garlic, allspice, bay leaf, cracked pepper, marjoram) for approx. 4 days. After removing from the brine, rinse and dry off. Place in baking dish, add carrot, parsnip, celery, onion and smoked plum. Add enough water to cover the pork knuckle and bake covered for approx. 4.5 hours at 160°C.
Before serving, spread smoked plum purée on the pork knuckles and place in the oven for 11 minutes at 210°C.
Soak the peas for 24 hours, then cook until soft in broth with heavy cream. Add previously-cooked potatoes and butter to the cooked peas. Mix everything and season with salt and pepper to taste.
Marinate the radishes in mustard, salt and pepper. Vacuum seal and cook for approx. 2 hours at 65°C.
Add the water from cooking the pork knuckles to the smoked plums, cook until soft and mix into a smooth mass. Add the mixed plums to the roast gravy and mix well.
Place the pork knuckle on a plate, add plum sauce, surround with pea purée and radishes. Serve with horseradish and nasturtium leaves.