Throwing Out the Pasta Cooking Water
It has become increasingly popular for recipes to suggest reserving some of the starchy cooking water from pasta and using it in a sauce, but if your recipe doesn't tell you to do it, or you're cooking without a recipe, you might just dump the entire pot of water into the sink when the pasta's done, letting that valuable liquid go down the drain. Before you carry the pot over to the sink, carefully dip a liquid measuring cup (preferably a glass one that can withstand high heat) into the pot and scoop up two cups of the water. Then, once you've drained and sauced your pasta, add a touch of the cooking water. The starch in the water will help the sauce adhere to the pasta. If the sauce (e.g., pesto or carbonara) isn't loose enough and seems to be making the pasta clump, a bit more water (say, a quarter cup) will thin it out.