1 tablespoon freshly grated Parmesan plus additional for serving
Directions
Fill a 6-quart kettle three fourths full with salted water and bring to a boil for spaghetti. Thinly slice garlic and finely chop anchovy. Cook pasta in boiling water until almost al dente.
While pasta is cooking, in a 12-inch heavy skillet cook garlic in oil over moderate heat, stirring, until golden. Remove skillet from heat and stir in anchovy, zest, red pepper flakes, and 1/2 cup pasta cooking water.
Ladle out and reserve 1 cup additional cooking water and drain pasta in a colander. Add pasta to garlic mixture and cook over moderately high heat, tossing and, if necessary, adding enough reserved cooking water to keep pasta moist, about 2 minutes, or until pasta is al dente. Add parsley, 1 tablespoon Parmesan, and salt and pepper to taste and toss well.
