Bring a large pot of water to a boil, season with salt.
Sauté onions in 2 tablespoons of olive oil in a large skillet over medium heat until translucent, about 5 minutes.
Add lamb and brown well until the meat is no longer pink. Deglaze by pouring red wine into the pan. Scrape up all the browned bits from the bottom until smooth, season with salt.
Add sauce and bring to a simmer.
In a separate small skillet, combine remaining olive oil, garlic, rosemary and chili flakes and cook over medium heat for 2 minutes. Add this mixture to the sauce.
Cook pasta according to package directions.
Drain pasta and toss with sauce, top with cheese before serving.
