I have been standing in front of a basket in the produce section of the Columbus Circle Whole Foods for two minutes. There is no identifying name card or price tag on it. If you didn't know any better, you probably wouldn't even notice the contents of this particular basket. But even though Whole Foods has neglected to put a price on them, I have an idea of their going rate, and I have been eyeing them covetously for what seems like an eternity, gently picking them up one at a time to estimate their weight as I run and re-run cost-benefit analyses in my head.

Whole Foods is selling fresh cèpes, also known as porcinis, the king of mushrooms. They are showing some wear and age, slightly browned and wrinkled--a copule of them are even bruised. But they smell like a hardwood fire in a thousand-year-old forest after the rain, and they are enormous. I have never seen whole, fresh porcini mushrooms for sale in New York. I remember reading somewhere that porcinis are being intermittently foraged in Oregon, but I think most of them still come from Europe, and then only in dried form. Will I ever have this chance again? How much could they possibly cost? In another aisle, chanterelles are going for over twenty dollars a pound. Could porcinis be as much as forty? How many could I afford to buy?

I walk up to the checkout aisle, my covetousness turned to shame. I have four huge cèpes in my basket. I picked up a few other items too, in an effort to justify to myself what I expect to be a grocery bill of over fifty dollars by lowering the mean per-item cost. As the clerk tallies my purchases, I brace myself for an embarrassing total. But it doesn't come. Instead, the clerk asks me for less than fifteen dollars for my mushrooms, some assorted greens and herbs, and a modest cut of meat. I pay her and take my groceries into the subway, wondering if I've been had. Arriving home, I take out the mystery item and examine it thoroughly. They still look like porcinis to me. How did I get out of Whole Foods with these things for less than twenty bucks?

I examine my receipt. There is no entry for porcinis. Instead, there is a charge of just over three dollars for just over a pound of portobello mushrooms. Now I know that it's the checkout clerk, not I, who's been had. Portobellos are easily distinguished from porcinis by looking at the underside of their caps. Where portobellos have dark, brittle gills underneath, porcini, being members of the genus boletus, have no gills, but rather a spongy network of microscopic pores through which they disseminate their spores. My shame now turns to guilt, as I realize that the checkout clerk simply didn't recognize what I was trying to buy, and mistakenly charged me for a far less expensive item than the one I was actually purchasing. Almost immediately, I begin rationalizing my good fortune by recalling law school lectures about unilateral mistakes of fact, but mostly I'm just overjoyed that I was able to spot these prizes and acquire them so cheaply. I am somewhat comforted by the fact that the checkout clerk's mistake is unlikely to be discovered, and thus that my gain will not come at her expense.

I use the caps of my practically-free fresh porcini to make a hearty ragout, coarsely dicing them and sautéeing them in olive oil with garlic and thyme, adding a bit of homemade chicken stock, sea salt, black pepper, and a dash of sherry vinegar. The ragout, served on slices of crusty bread, is a magnificent and rare meal in itself. And the experience is a vindication for my sometimes overbearing, sometimes pedantic, sometimes snobbish attention to gastronomy. Knowledge has value, and in this case my knowledge (or the poor checkout clerk's lack thereof) carried a price. When I contemplate a lifetime of seeking out this type of knowledge and account for the hidden pleasures it allows me to discover, I have no doubt that my life will be richer for the effort. More often than not, my exploration and experimentation leads to disappointment or frustration, but every once in a while it yields a moment of perfect, sublime satisfaction. On balance, it's a price I'm more than willing to pay.