Cut the pork shoulder into bite-size pieces and put them in a medium stockpot. Add enough cold water to completely cover the meat and bring to a rapid boil over medium heat. Reduce the heat and cook at a simmer for about 1 hour, occasionally skimming off and discarding the foam. After an hour, add the bay leaf and the allspice and continue cooking over low heat.
While the broth is simmering, shred the carrot using a box grater. Peel and dice the onion. Add a little oil to a sauté pan placed over medium heat and sauté the shredded carrot and the diced onion until fragrant. Add the sauerkraut. Ladle some of the broth into the pan so the vegetables don’t dry out. Once the vegetables are tender, take the pan off the heat.
Peel and dice the potatoes and add them to the broth. Simmer for about 20 minutes and then add the sautéed vegetables to the pot. Bring everything to a rapid boil, reduce the heat, simmer the soup for about 5 minutes, and remove from the heat. Season with a little salt and freshly ground pepper and let rest a little before serving.
