The chocolate chip cookie is a baked cookie made from a butter-and-sugar dough studded with chocolate chips or chunks, giving a crisp edge and a soft, chewy center. Unlike a chocolate cookie, where cocoa flavors the dough itself, a chocolate chip cookie uses a plain dough with separate pieces of chocolate folded in. It was invented in 1938 by Ruth Wakefield at the Toll House Inn in Whitman, Massachusetts, after she cut up a bar of Nestle semisweet chocolate and added the pieces to a batch of dough, expecting them to melt; instead they held their shape, creating pockets of chocolate. Nestle later printed the recipe on its chocolate chip packaging, helping make the cookie a fixture of American baking. Common variations add nuts, oats, or espresso powder, or swap in dark, milk, or white chocolate.