In a large heavy-bottomed saucepan, cook the onions in oil and butter, on medium-high heat until they are translucent. Add the dried thyme and stir. Add the lamb and brown on a high heat to seal in juices. Add carrots, and pearl barley. Pour in the Chicken Stock so that it almost covers the meat and vegetables. Season with salt and pepper, and add Bouquet garni. Cover and cook on low heat for 2 hours, being careful not to boil. Place potatoes on top of the stew, cover and cook for 30 minutes until the meat is falling beautifully off the bones and the potatoes are fork tender.
Serve the stew in large flat soup bowls, and drizzle Herb Butter over the potatoes or garnish with parsley and chives.
Preheat the stockpot. Combine ingredients in a large heavy-bottomed saucepan and cover with water. Bring to boil and simmer for approximately 30 minutes. Then let it cool down and skim off the fat.
Herb Butter: Melt butter in a small saucepan. Add parsley, chives and thyme.