In a large oven safe pot or roasting pan saute onions in oil over medium heat.
Add meat and brown well on all sides.
Mix in beans; stir continuously until the beans start to shrivel. Stir in the barley. Add potatoes and add just enough boiling water to cover the meat and potatoes. Mix in dry soup mix and garlic. Season with salt and pepper. Bring to a boil, lower heat and simmer partially covered for 20 minutes on stove top.
Preheat oven to 100 degrees C.
Cover pot tightly and place in preheated oven. Allow to cook overnight for at least 10 to 15 hours. Check periodically to make sure you have enough liquid to cover; add small amounts of water if needed. Do not stir; stirring will break up the chunks of potatoes.