Bring a large pot of water to a boil for the pasta.
Heat the EVOO, four turns of the pan, over medium heat. Add the anchovies and cover the pan with a splatter screen or lid. Shake until the anchovies begin to break up, reduce the heat a bit, then uncover and stir until the anchovies melt into the EVOO. Add the chili pepper and garlic, then stir for a couple of minutes more. Douse with a bit of vermouth and reduce the heat to low.
When the water is boiling, salt the water and cook the pasta to al dente. Reserve a cup of the starchy cooking water before draining the pasta and add it to the garlic and oil sauce, along with the parsley. Drain the pasta and toss to combine. Turn an additional minute in the sauce for the pasta to absorb the flavors.
Puttanesca Sauce: To turn this sauce into a Puttanesca, add 2 pints cherry tomatoes to the Aglio e Olio sauce, cover and cook over medium-high heat to burst the tomatoes, 7-8 minutes. Gently mash them up with a wooden spoon and stir in a handful of pitted oil-cured black olives and a few tablespoons of chopped capers. Add the parsley and toss with starchy cooking water and penne pasta.
White Clam Sauce: For a white clam sauce, add 2 tablespoons chopped thyme and 2 pounds of manila clams to the Aglio e Olio sauce. Cover to open the clams, then add 3 tablespoons butter and the juice of 1 lemon. Stir in parsley and starchy cooking water and toss with linguine.