CHOCOLATE CHIP COOKIES

CHOCOLATE CHIP COOKIES COME IN VARIOUS styles, with significant differences in texture, size, and flavor. The dough is a basic sugar cookie, in which some of the granulated sugar has been replaced by brown sugar, which gives them a caramel flavor. Of course, the dough is also studded with chocolate chips and, often, nuts.

Traditional recipes follow the Tollhouse cookie model, made famous on packages of Nestlé chocolate chips. This recipe dates back to the 1930s when Ruth Wakefield, owner of the Toll House Inn in Whitman, Massachusetts, cut up a chocolate bar and added the pieces to a cookie dough. She eventually sold the recipe to Nestlé, which introduced the chocolate morsel in 1939.

These cookies are on the small side (about 2 inches in diameter). The edges are thin, crisp, and golden brown. The center of the cookie is thicker and will bend when the cookies are warm but hardens as the cookies cool and snaps after several hours. The center of this cookie is often cakey, but should not be dry.

The original recipe calls for equal parts of brown and granulated sugar. We found that we like the caramel flavor that the brown sugar gives this cookie and have increased the ratio of brown to granulated sugar to two to one. Modern Tollhouse recipes often omit the water that was part of the original. We found that the water makes the cookies a bit moister and should be added.

An attractive variation on the traditional chocolate chip cookie is the oversized cookie that in recent years bake shops and cookie stores have made their reputation (and a lot of money) by selling. Unlike the traditional recipe made at home, these cookies are thick right from the edge to the center. They are also chewy, even a bit soft. Although we knew at the outset that molding the dough rather than dropping it into uneven blobs would be essential to achieving an even thickness, we didn't realize how challenging making them really chewy would be.

We added more flour or ground oats (as some recipes suggest), which helped the cookies hold their shape and remain thick, but made the texture cakey and dry rather than chewy. When we tried liquid sweeteners, such as molasses and corn syrup, the dough spread too much in the oven and the cookies baked up thin.

At this point in our testing, we decided to experiment with the butter. Some chewy cookies start with melted rather than creamed butter. In its solid state, butter is an emulsion of butter and water. When butter is melted, the fat and water molecules separate. When melted butter is added to a dough, the proteins in the flour immediately grab onto the freed water molecules to form elastic sheets of gluten. The gluten makes a cookie chewy.

Our first attempt with melted butter was disappointing. The dough was very soft from all the liquid, and the cookies baked up greasy. Because the dough was having a hard time absorbing the liquid fat, we reduced the amount of butter from sixteen to twelve tablespoons. We also reduced the number of eggs from two to one to make the dough stiffer.

The cookies were chewy at this point, but they became somewhat tough as they cooled, and after a few hours they were hard. Fat acts as a tenderizer and by reducing the amount of butter in the recipe we had limited its ability to keep the cookies soft. The only other source of fat is the egg. Since our dough was already soft enough and probably could not stand the addition of too much more liquid, we decided to add another yolk (which contains all the fat) and leave out the white. The dough was still stiff enough to shape. When baked, the cookies were thick and chewy and they remained that way when they cooled. Finally, we had the perfect recipe.