From America's Test Kitchen Season 2: Pesto, Carbonara, and Salad
Pasta with pesto makes for a satisfying, summery meal. But getting pesto right isn’t always so easy; the sauce can be anywhere from too thin and watery to too thick and overpoweringly garlicky. Our goal was to heighten the basil and subdue the garlic flavors in pesto so that each major element balanced the next. We started by briefly blanching whole unpeeled garlic cloves to tame their flavor and prevent them from taking over the sauce. Then we bruised the basil in a plastic bag with a meat pounder (you could also use a rolling pin) to unlock its flavor; we found that this method released the most herbal flavors from the basil. With the basil flavor boosted and the garlic toned down, it was time to process the ingredients with toasted nuts and stir in the Parmesan. Finally, we reserved some of the pasta cooking water, which was essential to thin out the pesto once it had been added to the pasta. The water also softened and blended the flavors a bit, and highlighted the creaminess of the cheese and nuts.
Basil usually darkens in homemade pesto, but you can boost the green color by adding the optional parsley. For sharper-flavor, substitute 1 tablespoon finely grated Pecorino Romano cheese for 1 tablespoon of the Parmesan. For a change from bow-tie pasta, try long, thin pasta such as linguine or curly shapes, such as fusilli, which can trap bits of the pesto.