Cut lamb and vegetables into bite-sized pieces.
Heat oil in a pot and brown the lamb.
Add onion, carrot, potato, and celery, then sauté together.
Pour in water or broth and bring to a boil.
Season with bay leaf, salt, and pepper.
Simmer on medium-low heat until the vegetables and meat are tender.
Taste and adjust seasoning if needed.
Serve in a bowl.