Since Nestlé first began printing the recipe for Toll House cookies on the back of chocolate chip bags in 1939, bakers have been trying to improve upon this classic. America's Test Kitchen imagined a moist and chewy chocolate chip cookie with crisp edges and deep notes of toffee and butterscotch to balance its sweetness. After baking countless batches of cookies, here's what they found:

• Melting a generous amount of butter before combining it with other ingredients gave the desired chewy texture. Since they were melting butter, they browned a portion of it to add nutty flavor.
• Using a bit more brown sugar than white sugar enhanced chewiness, while a combination of one egg and one egg yolk yielded supremely moist cookies.
• For the crisp edges and deep toffee flavor, they allowed the sugar to dissolve and rest in the melted butter. That meant setting aside the cookie dough for 10 minutes, and stirring several times, until the butter-sugar mixture resembled shiny frosting. Then, they added the flour and chips and shaped the dough into balls.

Get the recipe at America's Test Kitchen (free registration required) »