Heat oil over medium high heat in a large pot. Brown the lamb pieces in batches. Remove the meat and reserve. Add the onions, garlic, carrots, bay leaves, dried oregano, black pepper, and potatoes. Cook until the potatoes are lightly browned. Deglaze the pot the red wine vinegar. Add the lamb pieces. Allow the liquid to reduce until dry. Add the lemon juice and yogurt. Mix well. Add water and bring to a boil. Reduce heat, cover, and simmer slowly for 1 to 1 1/2 hours until the lamb is tender. Periodically skim off any froth that has risen to the top of the pot. Season with salt and black pepper to taste. Serve in bowls or soup plates. Garnish with a dollop of yogurt and serve with pita bread.
*To strain yogurt, place yogurt in a cheesecloth and tie with a short piece of string. Place cheesecloth pouch into a strainer and place over a medium bowl. Let sit in refrigerator for 1 hour. Discard liquid and remove yogurt from cheesecloth.
Recipe courtesy of Mina Newman, Layla Restaurant