New York Times food writer Julia Moskin has published an article on the art and science of using butter in cookie recipes. Baking aficionados know that using butter is critical, but Moskin delves much farther into the subject, unearthing a wealth of interesting information and anecdotal evidence. Until I read the article, I didn't realize how fickle butter is about its melting point. Moskin says, "For mixing and creaming, butter should be about 65 degrees: cold to the touch but warm enough to spread. Just three degrees warmer, at 68 degrees, it begins to melt." Butter is comprised of fat globules suspended in an emulsion of water. Once butter has been melted, that emulsion is broken, and the butter will never be the same again. Anyone who has accidentally over-heated butter then tried letting it cool off can attest to this! You're left with a remarkably unappealing puddle of congealed fat, with a thin layer of yellow oil floating on top. Butter at the proper temperature can hold a lot of air, if it's been properly whipped. When you cream butter into sugars, you're not just mixing everything up and softening the butter. You're whipping in air, just as you would if you were making a batch of whipping cream. If the butter is too warm when you start creaming it, it won't hold that structure. How do you know when your butter is at the right temperature to be creamed? It should still be chilled, but "takes the imprint of a finger when gently pressed." Moskin also covers the difference between different kinds of butter. American butter has a lower fat content (80%) than European butter (82%). Furthermore, butter from Europe is made with "slightly fermented cream." Which sounds a little gross to me, but conventional wisdom among epicures is that the resulting butter tastes far better. Trauger Groh, "Biodynamic Farmer, Author & Lecturer" has an article online titled The Case For Butter. In it, he points out that butter has historically been made from slightly fermented cream (i.e. sour cream). It turns out that the switch to fresh cream happened in the 1940s, to meet the demands of mass production. At the time, making butter from sour cream required that the machinery sit idle for a period of time, to allow the cream to be skimmed. Mass market butter producers found that they could run their machinery constantly if they used fresh cream, which doesn't require skimming. By not having to waste time idling their machinery, the manufacturers saved money. Sour cream butter is sold in the United States at specialty stores. Look for "cultured" on the label. If you can't find it at your local gourmet grocery (or if, like me, you don't really have a "local gourmet grocery") you can - as with so many other silly items - order it from Amazon. Back to the original article, Moskin has included several mouth-watering recipes for butter-based cookies, including Buttery French TV Snacks, Currant Ginger Shortbread, and Orange Butter cookies. Super yum!