Reader Dianne writes:
I hope you can solve my mystery. I have been making World Peace Cookies successfully for several years, until now. Suddenly my cookies are coming out flat. And the edges are sometimes bubbled, kind of like Florentines. I am using the same recipe and the same oven and the same oven temperature (325) as before. Was my dough not chilled enough? Is my oven getting inaccurate? Maybe too hot? Did I beat the butter and sugar too much? All of the above?
Queries like this come in regularly in regard to cookies — especially chocolate chip cookies — usually in the late fall. That makes me suspect that Dianne’s problem, assuming nothing has changed in her technique, is with her ingredients, specifically her butter. Cows change diets in the fall, or at least they do in some parts of the country. That change in diet can cause the composition of the cows’ milk to change, and with it the characteristics of the milk fat.
You may remember me blathering about fat molecules in the past. They’re “E”-shaped. A “backbone” of glycerol with three fatty acids attached. Cow’s milk, provided the cow is well nourished, will always have lots of fat molecules in it. However the fatty acids that make those molecules up can change according to what the cow has been eating. And that can change the way the fat behaves. For instance, it can change the butter’s melting point by a degree or two, and that can have an impact on the degree to which a cookie spreads.
If the butter in the cookies has a lower-than-normal melt point, it will liquefy early in the baking process, causing the batter to run before the cookie can set up. This is what I suspect is happening in Dianne’s World Peace cookies. My suggestion is to change butters and see what happens. The irony here is that “better” butters, i.e. artisan farm butters, are more likely than mass-market butters to have variability problems, since big factory creameries will tend to feed their cows a more consistent diet year-round. So, try a cheaper, store brand butter first.
Dianne, get back to me and let me know if I gave you the right answer!
UPDATE: Dianne writes:
I think you may be on to something. I used some European style butter from Central Market in these cookies. I normally use supermarket brand butter. (I have had great results with the Kroger house brand of butter.) I will go with my usual butter next time and see what happens.
Bingo. Now if I can only get Rehrücken right…