Put the oxtail, pig feet and ear in a pot, and cover with salted water. Bring to a boil and skim. Lower the heat and simmer for 1 hour 30 minutes, then add the onions, carrots and turnips. Continue to cook for 45 minutes. Add the cabbage and simmer for another 45 to 50 minutes. Boil the potatoes. To serve place the meats in a circle on a serving platter, the pig ear cut into large slices and the vegetables in the middle. Serve the potatoes separately. Garnish with mustard, pickles and coarse salt.