Warm the oil in a dutch oven or stainless steel pot on medium heat. When warm, add lamb and brown on all sides.
While the lamb is browning, dice the onions, and cut the potatoes into quarters (or halves if they are large). Trim the stems off the green beans.
Remove the lamb from the pot and deglaze if there are any pieces left sticking. You can use a little water to scrape the pieces off.
Add extra oil to the pot if necessary, then add the onion. Saute until onions are soft and translucent.
Add the lamb back to the pot, along with potatoes and green beans. Fill the pot with 6 cups of water or until only an inch or so is left uncovered. Everything does not need to be completely covered, as you can come back and stir once or twice.
Bring the water to a boil, then turn down to simmer for 2 hours.
Serve in bowl like soup or with rice or grain of choice.