Bring a pot of water to a boil. Season liberally with salt and cook pasta 5 minutes.
Meanwhile, heat olive oil, 4 slow turns of the pan, over medium heat. Add garlic, chili flakes and rosemary, stir 2 minutes then add wine and bring to boil. Reduce heat to a low, rolling simmer.
Drain pasta and add it to the wine. Cook, stirring occasionally, for 3-4 minutes until pasta is cooked to al dente (to the bite/teeth). Add butter and toss to gloss the pasta. Serve in shallow bowls topped with Pecorino.