The ingredient list could hardly be shorter, but making spaghetti with garlic and oil as good as the version served at Italian restaurants takes attention to technique.
The key, say Chowhounds, is to cook the garlic slowly in plenty of good olive oil over low heat. This assures a toasty garlic flavor and garlicky oil without bitterness or burning. Most hounds cook the garlic until it is golden, but don't let it turn brown. Whether you slice, mince, or crush the garlic in a press is a matter of personal taste, as is the amount you use. Some folks reserve a bit of minced or crushed garlic to add near the end, for a hotter layer of flavor. Sauté a pinch of red pepper flakes or some crumbled dried red chile with the garlic if you like.
To add an extra dimension, consider using garlic-infused oil to cook your garlic in. "I make 'garlic confit' pretty regularly—basically I just simmer whole cloves of garlic in oil until they're soft and lightly caramelized," says biondanonima. "The leftover oil obviously has lots of sweet roasted garlic flavor, and it definitely gives this type of dish an extra garlic kick."
Many hounds add the cooked spaghetti to the pan with the garlic. "This is the key," says Westminstress. "If you finish cooking the pasta in the sauce with some of the pasta cooking water, the pasta will absorb the flavor of the sauce and taste much better, and it'll have more of a 'sauce,' not just a slick of oil."