Christmas cookies are greater than the sum of their parts. We don’t need a food chemist to tell us that.
But we do need food scientists to explain the role each ingredient plays in creating that perfect combination of flavor, texture and appearance that make all those cookie platters so hard to resist every December.
With the help of some experts, we’ve deconstructed the cookie for a closer look at each part:
Fats used in cookies can include butter, solid vegetable shortening and/or margarine. Because butter melts the minute the hot air of the oven hits it, cookies made with butter spread more than those made with margarine or shortening.
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There’s also the question of taste. Experts generally prefer the real thing over margarine or butterflavored shortening.
“I always bake with all butter at holiday time,” says Dave Schmidt, executive director of the Wisconsin Bakers Association and a certified master baker. “It’s up to the individual, but butter is going to give you better flavor.”
Susan Reid, a baking expert and cookbook editor from King Arthur Flour in Norwich, Vt., agrees. “Personally, I don’t believe in margarine,” she says.
Schmidt and Reid emphasize, though, that if you choose to bake with margarine, it needs to be stick, not tub margarine, which contains oil and is too soft for baking.
Beyond the choice of fat, “the most important thing with whatever fats you use is to make sure they’re at room temperature,” Schmidt says.
As for the question of salted vs. unsalted butter, Reid says salted butter easily can be substituted if that’s what you have on hand. Each stick contains 1/4 teaspoon of salt, so reduce salt accordingly.Sugar
Recipes are specific about the type of sugar that’s best for each type of cookie for a reason: While all sugars add sweetness, each type brings other qualities, too.
White granulated sugar produces the crispiest texture, Reid says, while brown sugar, in addition to adding color, makes cookies that are “bendier” and more chewy. That’s because brown sugar is made from white sugar with molasses added. Because molasses is liquid at room temperature, it interferes with recrystallization as cookies cool, keeping them softer. Some recipes blend the sugars to achieve a combination of attributes.
Powdered sugar, sometimes called confectioners’ sugar, is a very fine sugar with 3 percent cornstarch added by weight. While the cornstarch is there to prevent clumping, the presence of cornstarch means there’s less room for flour in the dough, resulting, for example, in the distinctively light, fine texture of Mexican wedding cookies.
For a bit of crunch when a recipe calls for cookies to be rolled in or sprinkled with sugar, you can’t beat turbinado or other coarse crystal-type sugars. But they can’t be substituted for white or brown sugar in the cookie dough.
The same is true for ultra-fine sugar, which is great for beating with egg whites for meringues because it dissolves so well. But it’s a poor choice for cutouts, especially, so don’t use it in place of regular granulated sugar, Schmidt cautions.
“If you want a cookie to hold its shape, avoid ultra-fine sugar,” he says.
Mixing technique is important, too, Schmidt says. “Never blend more than two minutes when you’re incorporating the sugar and fats.”
Bread flour, cake flour and pastry flour all have their place, but when it comes to cookies, for the most part, all-purpose flour works best.
Even within that parameter, though, home bakers have a choice: bleached or unbleached? Until recently, bleached flour was recommended for cookies, on the theory that cookies made with bleached flour would spread less and be crisper.
“The argument between bleached and unbleached flour has been going on for years,” says Schmidt. His final verdict: “It really doesn’t make any difference.”
Reid, meanwhile, advocates unbleached flour as a healthier choice.
“Why sign on for chemicals you don’t need?” she asks. “There’s no reason for it to be in there unless it’s cake flour.” Producing dense cakes calls for a different chemical structure, she explained.
Another health-conscious choice related to flour is the desire to incorporate whole grains.
Reid suggests replacing no more than 25 percent of the flour in a recipe with whole-wheat flour, and she points out that adapting favorite recipes can require “a lot of testing and trial and error.”
She also advocates white wholewheat flour as “a good place to start.”
She adds that chocolate in a recipe can disguise the whole-wheat taste that some people may not be used to, and she has this tip for those serving whole-wheat products to the unconverted: “Eat first, tell later.”Baking soda, powder
At least one of these leaveners is found in most cookie recipes. Which one depends on other ingredients in the recipe. Baking soda, which generally produces a crisper cookie, needs an acidic ingredient, such as cocoa, buttermilk or molasses, to activate it.
Baking powder, which produces a chewier cookie, does not. Reid points out that both ingredients lose their potency if they’ve been in the cupboard a long time.
“If you haven’t baked since last Christmas, buy new,” she says.
You can test baking powder by mixing a little with water and baking soda by mixing it with vinegar. In both cases, it should fizz.
She also offers this suggestion if you’d like your cookies softer and chewier: Add a tablespoon of corn syrup.Eggs
Large eggs (1 3/4 to 2 ounces each) are the standard for recipes, says Reid. Eggs act as a binder and a tenderizer in cookies. In bar cookies, they can result in a more fudgy or cakelike texture, too.
All of the fat in an egg is in the yolk, which is also the source of the egg’s emulsifying power. Most of the protein is in the white. The fat is a tenderizer, while the protein provides structure. Whites, which can be beaten to trap air, give meringue-type cookies their appealing lightness.