Heat the olive oil in a large pot over medium heat. Add the lamb cubes and brown them on all sides, about 6 to 8 minutes. Remove the lamb and set it aside.
Add the onion and garlic to the pot. Cook until the onion softens, about 4 minutes. Sprinkle in the flour and stir for 1 minute to coat the vegetables.
Return the lamb to the pot. Pour in the lamb broth and add the thyme, bay leaf, salt, and pepper. Bring the mixture to a simmer.
Add the turnips and carrots. Cover and cook on low heat for 1 hour, stirring occasionally, until the lamb is tender.
Stir in the green peas and cook uncovered for 5 more minutes. Remove the bay leaf before serving. Sprinkle with chopped parsley.