The chocolate chip cookie was invented by Ruth Graves Wakefield at the Toll House Inn in Whitman, Massachusetts in 1938 — she chopped a bar of Nestlé semi-sweet chocolate and mixed the pieces into her butter cookie dough, expecting them to melt. They didn't — they softened but held their shape, and the chocolate chip cookie was born. Nestlé acquired the recipe in exchange for a lifetime supply of chocolate and printed the "Toll House Cookie" recipe on every bag of Nestlé chocolate chips, where it remains today. The recipe on the back of the yellow bag is the most reproduced recipe in American baking history.
A round, golden-brown cookie, approximately 8cm in diameter, with a slightly crispy edge, a soft, chewy centre, and pockets of melted-but-intact chocolate chips throughout. The dough: butter, white and brown sugar (the brown sugar provides chewiness and caramel depth), eggs, vanilla, flour, baking soda, salt, and semi-sweet chocolate chips. The exterior should be golden; the interior should be barely set — slightly underdone by bread standards, which produces the chewy texture.
1) Cream the butter and sugars until light and fluffy — the air incorporated during creaming provides lift. 2) Brown sugar is essential — its molasses content provides moisture and chewiness. All-white-sugar cookies are crisper and thinner. 3) Chill the dough for 24-36 hours — the cold rest hydrates the flour, develops flavour through enzymatic activity, and firms the fat for a thicker cookie. Fresh-baked dough produces a flat, spread-out cookie. 4) Slightly underbake — pull the cookies when the edges are golden but the centre still looks slightly raw. The centre sets as it cools. A fully baked cookie is a dry cookie.
The New York Times / Jacques Torres cookie recipe (2009) — brown butter, bread flour, two types of chocolate (bittersweet discs and chocolate chips), sea salt on top, 36-hour cold rest — is the recipe that launched a thousand food blogs and represents the "serious" chocolate chip cookie movement. Levain Bakery (New York) — the 6-ounce, barely baked, molten-centred walnut chocolate chip cookie — is the extreme expression. Sea salt flakes on top (Maldon) — the salt-sweet contrast on a warm cookie is the contemporary upgrade.
Not chilling the dough — flat, thin, crispy cookies (if that's what you want, fine; if you want thick and chewy, chill). Over-baking — the most common home-baking error. The cookie should look underdone when it comes out of the oven.
Dorie Greenspan — Baking with Dorie; James Beard — American Cookery