Cut lamb into cubes.
Heat oil in a heavy saucepan, add the lamb and cook until lightly browned. Remove meat from the pan and add chopped onions and chopped garlic clove. Cook for 3 minutes the add flour and stir, heating until the mixture browns.
To the onion mixture, gradually add beef broth while stirring. Return the meat to the saucepan. Add salt, pepper, rosemary, and bay leaf. Cover and simmer for 1 hour, or until the meat is almost tender.
Add diced potatoes, sliced carrots, and diced turnips. Cook for 30 minutes longer. Add frozen peas and pearl onions, and continue cooking until the peas are tender, about 10 to 15 minutes.