Bring a large pot of water and the 2 tsp salt to a full boil. The water should bubble steadily before the pasta goes in.

Add the pasta and cook it for the time listed on the package. Start checking near the end so the center stays pleasantly firm rather than soft.

Before draining, scoop out 1 cup of the cloudy cooking water. This starchy water is the key to a sauce that looks glossy rather than oily.

Drain the pasta in a colander and let it stand for 1 minute. The noodles should remain hot and lightly damp, with no rinse under running water.

Tip the pasta into a large bowl instead of returning it to the hot pot. Moving it away from direct heat protects the pesto’s fresh green color and delicate aroma.

Add the pesto and 1/4 cup of the reserved pasta water, then toss vigorously. Add more water as needed until the pasta makes a gentle wet sloshing sound and wears a silky sheen.

Taste the pasta and adjust with more salt and pepper if desired. The sauce should cling to the noodles instead of collecting at the bottom of the bowl.

Serve immediately with fresh Parmesan. Steam should carry the scent of basil, garlic, and cheese as the pasta reaches the table.