Cut the mutton meat into pieces and season with salt and pepper. You can tenderize it lightly. Heat the oil and braise the meat on all sides.
Arrange the meat in a clay pot. Pour the vegetable broth over it and put the clay pot in a cold oven. Heat it to 392°F (200 °C) and bake the meat about 30 min., then lower the heat to 356°F (180 °C) and bake another 180 min. Check on the meat and if needed pour in more water or broth.
Heat the oil from the frying and braise the finely chopped bunches of leeks. Add the all purpose spice, Worcestershire sauce and 1/2 cup water and saute until the leeks soften. Add this mixture to the mutton and bake a final 15 min.