Bring a large pot three-fourths full of salted water to a boil.
Preheat the broiler on High and move rack to 6 inches under heating element. Cut the bell peppers in half lengthwise and remove the stems, seeds and ribs. Arrange cut sides down on a baking sheet, flattening the peppers so the entire outside is exposed to the broiler heat.
Broil until the skins blacken and blister, about 10-15 minutes. The more black char and blistering that covers the surface, the easier the peppers are going to be to peel.
Transfer peppers to a paper bag and let stand until the peppers cool and the skins loosen, about 15 minutes. (If you don't have a paper bag, place the peppers in a glass bowl and cover with a plate.)
Using your fingers or a small knife, peel off the skins (If the entire skin won't come easily off, don't worry, just do your best). Cut the peppers lengthwise into strips. Set aside.
In a blender or food processor, combine the roasted bell pepper strips, garlic, olive oil, and salt. Process until smooth. Cook's note: My Blendtec blender is a powerhouse and can process this puree completely smooth. My food processor yields a less smooth mixture and that is the consistency I prefer. (Photos are shown with the food processor-processed sauce.)
Add the pasta to the boiling water and cook until al dente, according to instructions. Drain and transfer to a warmed serving bowl. Immediately pour the puree over the top and toss well. Sprinkle with the parsley and serve at once.