Bring the water to a boil with the two kinds of salt. Allow it to cool, then pour it over the pork, cover it, and brine it for 12 hours.
Remove the pork from the brine and pat dry. Then wrap it tightly in plastic wrap and then in aluminum foil. Fold the ends tightly and simmer at 62°C for 24 hours.
Remove the cooked meat from the water and allow it to cool in ice water. Take the pork out of the foil, pat dry and cut into 2 cm thick slices.
Use a melon baller to create 10 small 1 cm balls of sweet potato.
In a small pot, melt the butter, add the sweet potato balls and thyme, add the water, bring to a boil, cover and simmer for 20 minutes. Once the sweet potato pearls are cooked through and the water has boiled off, finish with butter.
Mashed sweet potato:
Sauté the sweet potatoes in butter, add cream and milk, season with salt and slowly cook sweet potatoes until done. The liquid will not have boiled off completely.
Blend in a mixer and strain through a sieve. Allow to cool down and season to taste.
Spicy plum jus:
Grind the spices and roast in a pan, deglaze with vinegar and add red wine and port. Boil until reduced by half. Add the Earl Grey leaves to the reduction, steep for 5 minutes, strain and let simmer overnight.
To finish the sauce:
Bring the poultry broth to a boil, add reduced spicy plum fond and add the butter. Put plums in hot sauce and season to taste.
Finishing & serving:
Lightly flour 2 slices of pork for each person and fry gently in canola oil for 2 minutes. Glaze meat with plum jus.
Refine the mashed sweet potatoes with one tablespoon of whipped cream.
Arrange two slices of pork neck with plums and spring onions. Garnish with sweet potato pearls.