Preheat the oven to 130 °C. Pour the chicken broth into a roasting pan and place the pork shoulder, skin side down, in the pan so that the skin is completely submerged in the broth. Allow to braise for about 3 hours.
For the sauce, dice the onion, carrots and celery. Sauté the onion without fat in a pot or pan. Sprinkle with a little powdered sugar.
Reduce the temperature. Add the carrots and celery and mix well. Add about 1 heaped teaspoon of tomato paste and mix well. Pour some red wine and let it reduce completely while stirring. Repeat this process 5 – 6 times to make a pasty base for a dark sauce.
After 3 hours, remove the roast from the oven.
Pour about 3/4 of the stock into the sauce base. Cut the buttery rind into a diamond shape. Place the roast with the rind facing up in the roasting pan with the remaining broth and braise in the oven at 230 °C for about 1/2 hour. Keep brushing with salt water. In the meantime, refine the sauce with peppercorns, cardamom pods, caraway seeds, marjoram and some ground allspice. Mix some starch with cold water and thicken the boiling sauce with 3 – 4 tablespoons of it. Bring to the boil again and simmer or steep very gently at a low temperature, adding slices of garlic and ginger. Remove the roast from the oven.
Pour the remaining broth into the sauce, stir, pour through a sieve and season to taste. Add salt if necessary. Serve with potato dumplings and coleslaw.
