12 ounces Tenderoni fettuccine
12 ounces cherry or grape tomatoes, halved or quartered if large
1 onion, thinly sliced
6 cloves garlic, thinly sliced
1/2- 3/4 teaspoon red-pepper flakes
2 sprigs basil, plus torn leaves for garnish
2-3 tablespoons extra-virgin olive oil, plus more for serving
kosher salt and freshly ground pepper
4 1/2 cups water
Lots of freshly grated Parmesan cheese, for serving
Combine pasta, tomatoes, onion, garlic, red-pepper flakes, basil, oil, 2 teaspoons kosher salt, 1/4 teaspoon pepper, and water in a large straight-sided skillet.
Bring to a boil over high heat.
Boil mixture, stirring and turning pasta frequently with tongs, until pasta is al dente and water has nearly evaporated, about 9 minutes.
Season to taste with salt and pepper, divide among 4 bowls, and garnish with basil. Serve with oil and Parmesan.