How to Make It
In a large skillet, heat the 2 tablespoons of olive oil. Add the onion, garlic and bell peppers, season with salt and pepper and cook over moderate heat, stirring occasionally, until the peppers are tender, about 10 minutes.
Meanwhile, in a pot of salted boiling water, cook the pasta until al dente. Drain, reserving 1 cup of pasta water.
Add the spaghetti, pasta water, tomatoes and parsley to the skillet and toss over moderate heat for 1 minute, then serve.