1. Preheat oven to 300 degrees Fahrenheit (150 degrees Celsius).
2. Combine tomato paste, balsamic vinegar, maple syrup, and spices. Spread liberally on lamb in a baking pan. Pour chicken stock halfway up the pan, being careful not to wash off the seasonings. Cover tightly and bake for four hours.
3. Allow to cool slightly, then shred the meat with one to two tablespoons of liquid from the pan. If making in advance (and I suggest you do), heat up the meat before serving in a frying pan so the pieces are slightly crisped.