Why Save Your Pasta Water?
Use a little cooking water to bring pasta and sauce together.
Scoop before you drain
Just before draining pasta, carefully scoop a cup of the cloudy cooking water into a heatproof mug. Set it near your sauce pan. Taking it late in cooking gives the water more starch than scooping it immediately after the pasta goes in.
Add a splash at a time
Put drained pasta into the sauce and toss over low heat. Add two or three tablespoons of cooking water and keep tossing. The liquid helps spread a thick sauce around the pasta; its starch helps the mixture cling.
Keep adding small amounts until the pasta looks glossy. Pouring the whole cup in at once can turn dinner soupy.
Taste at the end
Salted water adds seasoning too. Taste the pasta before reaching for more salt, especially when your sauce contains cheese.
Try the method in garlic butter pasta or creamy tomato pasta. Serve promptly: pasta continues to absorb liquid as it stands.