1. In a medium frying pan, heat the olive oil over moderately low heat. Add the garlic and the red-pepper flakes and cook, stirring, until the garlic softens, about 1 minute. Add the sliced mushrooms and the salt and cook until the mushrooms exude liquid, the liquid evaporates, and the mushrooms begin to brown, about 5 minutes.
2. In a large pot of boiling, salted water, cook the spaghettini until just done, about 9 minutes. Drain and toss with the mushroom mixture, the parsley, and the pepper.
Variations: Spaghettini with Garlic and Oil : Eliminate the mushrooms and reduce the oil to 7 tablespoons. Just cook the garlic and red-pepper flakes for a minute and toss with the remaining ingredients.
Spaghettini with Walnuts, Garlic, and Oil: Eliminate the mushrooms and reduce the olive oil to 7 tablespoons. At the end, toss in 2/3 cup of toasted and chopped walnuts.
Spaghettini with Salami, Garlic, and Oil: Eliminate the mushrooms and reduce the olive oil to 7 tablespoons. Cut 1/4 pound of sliced salami into thin strips and toss it into the spaghettini with the parsley and black pepper.
Wine Recommendation: The earthy taste of mushrooms goes wonderfully with the correspondingly earthy flavor of a pinot noir, while the assertive flavor of the garlic calls for a simple version of this wine. A bottle of Givry, Rully, or Mercurey from France will be your best choice.