
Cook the pasta in boiling salted water according to the package directions. Cook the pasta until al dente, then drain. Editor's Tip: Al dente pasta describes the texture of cooked pasta that is tender, firm and chewy when you bite into it.
In a large saucepan, cook the garlic and red pepper flakes in butter and oil, stirring constantly, until the garlic is golden, about one to two minutes. Editor's Tip: Garlic burns easily, so be watchful when adding it to a pan. And be sure to add the shrimp as soon as the garlic is cooked (see next step). Add the shrimp, and cook until they turn pink, two to three minutes. Working quickly, using a large slotted spoon, remove the shrimp from the pan to a plate or bowl. Keep the shrimp warm.
Add the wine (if using), lemon juice, lemon zest, salt and pepper. Reduce the heat and simmer, uncovered, until reduced and slightly thickened, five to seven minutes. Editor's Tip: Not sure how to zest a lemon? Just remove the yellow part of the skin while leaving behind nearly all of the white pith. You can do this delicately with a very sharp vegetable peeler and then mince up the strips or buy a zester, but the best tool for the job is probably a microplane grater.
Add the pasta, shrimp, Parmesan and parsley, and toss to coat. Cook until just heated through, and remove from the heat before serving.