📋 Instructions

1. 1Boil the pasta — Bring a large pot of well-salted water to a rolling boil at 212 F (100 C) and cook the fettuccine for 1 minute less than the package says, about 9 minutes, until it bends but still has a firm bite at the center. Scoop out 1 cup of pasta water before draining.
2. 2Melt the butter — In a wide 12-inch skillet over medium-low heat, melt the butter until it foams and smells faintly nutty, about 2 minutes at roughly 250 F (120 C). Do not let it brown.
3. 3Bloom the garlic — Add the grated garlic and stir for 30 to 45 seconds, just until the sharp raw smell softens into something sweet and the garlic turns pale gold, not brown. Burnt garlic turns the whole sauce bitter.
4. 4Build the roux — Sprinkle the flour over the butter and whisk steadily for 1 to 2 minutes at 250 F (120 C) until the paste looks smooth and glossy and smells like toasted bread. It should pull away from the pan in a soft mass.
5. 5Whisk in the milk — Pour the warm milk in a slow stream, whisking the whole time, then add the salt and pepper. Raise the heat to medium and bring it to a gentle simmer at 185 F (85 C), whisking until the sauce thickens enough to coat the back of a spoon, about 4 to 5 minutes.
6. 6Melt in the cheese — Pull the pan off the heat and stir in the Parmesan in three additions, letting each melt before the next. The sauce should look glossy and slide off the whisk in a slow ribbon.
7. 7Toss with the pasta — Add the drained fettuccine and toss over low heat at 165 F (75 C) for 1 to 2 minutes, splashing in reserved pasta water a tablespoon at a time until the sauce clings to every strand and pools slightly at the bottom of the pan.
8. 8Finish and serve — Stir in the parsley off the heat, taste for salt, and serve immediately in warm bowls with extra Parmesan at the table. The sauce tightens as it cools, so move quickly.