Heat olive oil in a large pot over medium heat. Add onion, carrots, and celery, and cook until softened, about 8 minutes.
Add garlic and sauté for 1 minute. Stir in ground lamb and cook until browned, breaking it apart with a spoon.
Add tomato paste and cook for another 2 minutes. Pour in red wine and simmer for 3–4 minutes.
Stir in crushed tomatoes, oregano, thyme, bay leaf, salt, and pepper. Bring to a simmer.
Reduce heat to low, cover partially, and cook for 1.5 to 2 hours, stirring occasionally.
Cook pappardelle according to package instructions. Drain and toss with the ragu.
Serve hot, topped with Parmesan and parsley if desired.