Cook's Illustrated

Solving the Mystery of the Chewy Chocolate Chip Cookie

Published January 1, 1996.

After testing 40 variations, we discover how to make a thick, chewy gourmet shop cookie at home.

The Problem

We tried innumerable published recipes claiming to produce thick, chewy cookies but were disappointed batch after batch.

The Goal

The quest began simply enough: We wanted to duplicate, at home, the big, delicious, chewy chocolate chip cookies bought in the trendy specialty cookie shops. For us, first and foremost, this genre of home-baked chocolate chip drop cookie had to look and taste like the ultimate, sinful cookie: thick (1/2 inch high), jumbo (3 inches in diameter), and bursting with chocolate. It also had to have a mouthwatering, uneven surface texture with rounded edges and be slightly crispy but tender on the outside and rich, buttery, soft, and chewy on the inside.

The Solution

One key element in achieving this cookie was melting the butter. According to food scientist Shirley Corriher, when butter is melted, free water and fat separate. When this melted butter is combined with flour, the proteins in the flour grab the water and each other to immediately form elastic sheets of gluten. This creates a product with a chewy texture. At the same time, the sugars and fats are working to inhibit gluten formation, which prevents the cookies from getting too tough. After numerous tests, varying the type of flour, the proportion of flour to butter, and sifting and not sifting, we decided that the best cookie resulted from unsifted, bleached, all-purpose flour, which has a lower protein content than unbleached. Also, the problem of the cookie hardening after several hours was eliminated by the addition of a single egg yolk; the added fat acts as a tenderizer.

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