Prepare the Greens: Bring a large pot of generously salted water to a boil.
Add the broccoli raab and blanch for 2-3 minutes until tender-crisp and bright green.
Using tongs, transfer the raab to a bowl, reserving the boiling water in the pot for the pasta.
Once cool enough to handle, coarsely chop the broccoli raab.
Sauté the Aromatics: In a large skillet over medium heat, warm 2 tablespoons (30 ml / 1 fl oz) of the olive oil.
Add the minced garlic and red pepper flakes.
Cook for about 30-60 seconds, stirring constantly, until the garlic is fragrant but not browned.
Cook the Greens: Add the chopped broccoli raab to the skillet.
Season with salt and pepper.
Stir well to coat the greens in the garlic-chili oil and cook for 2-3 minutes until heated through.
Remove from heat.
Cook the Pasta: Bring the reserved pot of water back to a rolling boil.
Add the perciatelli or bucatini and cook according to package directions until al dente.
Before draining, reserve about 1 cup (240 ml) of the starchy pasta water.
Combine and Serve: Drain the pasta and add it directly to the skillet with the broccoli raab.
Add the remaining 1 tablespoon (15 ml / 0.5 fl oz) of olive oil and a splash (about ¼ cup) of the reserved pasta water.
Toss everything together over low heat until the pasta is well-coated and a light sauce forms.
Add more pasta water if needed.
Serve immediately, topped with your choice of cheese if using.
Don't Skip the Pasta Water: That starchy, salty water is liquid gold! It helps the oil and garlic cling to the pasta, creating a silky, emulsified sauce instead of a dry dish.