Dear graduate, congratulations on your achievement!

From the list of ingredients (which must also include some baking soda or baking powder, mustn’t it?, unless you’re making meringues), the only possible culprit is the pecans. Nuts, because of their high oil content, are prone to going rancid. We’re surprised it takes a day for the rancid flavor to develop – perhaps they’re already on the border and the heat of the oven sets them on an inexorable downward spiral.

We store nuts in the freezer to lengthen their shelf life, but even with that precaution, we occasionally have to throw out rancid nuts. Pecan pieces may turn rancid in as little as a month if stored above 70°F (21°C). In the refrigerator, they should keep for 5 months, and as long as a year in the freezer. Pecan halves, with less surface area, will generally last twice as long as pecan pieces, and nuts in the shell, twice as long as that.

We suppose there’s the smallest possibility that your container is the problem, since we don’t know what it’s made of or what horrible smells it might be harboring. Next time you make your cookies, use nuts that you know to be fresh and taste them before adding them to the dough. Then, once cool, store at least some of your cookies in a pristine zipper-top plastic bag and the next day, they should be fine.

Now, hoping that resolves the cookie issue, let’s speak about another matter. There are more and more trained chefs, and is more and more mediocre (or worse) restaurant food. We would like you to take a pledge to be a good chef – no matter how clever or creative you are – to only use good ingredients, to only put them together in ways that produce real flavor. We are constantly amazed – and heartbroken – at the number of restaurants where you cannot count on getting consistently good food. We trust the ones where you cook will consistently be good.