Cut off some fat from the lamb and place it in a skillet preheated over medium heat. Melt the fat over medium heat. Preheat oven to 180 degrees Celsius.
Chop the onion roughly. Peel potatoes and cut into 4 pieces. Peel the carrots and cut into coarse pieces.
After 5-10 minutes, remove the fat from the pan and discard. Fry the lamb in fat for about 3 minutes over medium heat, turn over after 1.5 minutes. Place the lamb in a saucepan and sauté the carrots and onions in the remaining fat for two minutes, stirring frequently and turning the ingredients.
Place the onions and carrots on the lamb in a saucepan. Season with salt and pepper. Add Worcestershire sauce, pearl barley, and lamb stock. Place the potatoes on top, but do not mix with the rest of the ingredients. Add some more salt and pepper to season the potatoes. Cover the pot with a lid and place in the preheated oven and cook for 1 hour.
Melt butter in a saucepan over medium heat, whisk in flour. Cook for 2 minutes, stirring all the time to prevent the mixture from sticking to the bottom of the pan.
Remove the saucepan from the oven and pour the dressing over the flour and butter. Sprinkle with caraway seeds. Stir quickly with a fork or whisk. Add more salt and pepper if necessary.
Place the covered saucepan back in the oven for 10 minutes. Serve with red wine or Guinness.