Bucatini with Tomato, Guanciale, and Chile

Microwave rosemary on high in 20-second intervals until leaves are brittle, about 60 seconds. Remove leaves and grind to a fine powder with a spice mill or mortar and pestle; you should have about 1 teaspoon (Alternatively, very finely chop leaves.) Cook guanciale in a large skillet over medium heat, stirring often, until guanciale is browned and crisp, 10 –12 minutes. Transfer to a bowl with a slotted spoon. Cook onion in same skillet over medium heat, stirring often, until softened and golden brown, 8 –10 minutes. Return all but 2 tablespoons guanciale to skillet and add tomatoes, red pepper flakes, and rosemary powder. Bring to a boil, reduce heat, and simmer, stirring occasionally, until sauce is thickened, 5 –8 minutes. Meanwhile, cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente, 8 –10 minutes. Drain pasta, reserving 1 cup pasta cooking liquid Add pasta and 1/2 cup pasta cooking liquid to sauce. Cook over medium heat, tossing and adding more cooking liquid as needed, until sauce coats pasta, about 2 minutes. Serve pasta topped with Pecorino and remaining 2 tablespoons guanciale and drizzled with oil.