Pepito de Iberico: At $20, it's the most expensive (legal) substance on Washington's streets. (Tim Carman/The Washington Post)

Forking over a Jackson for a small wrapped product — one purchased near a public park in stark daylight in full view of the police — is not an act one should do casually. This is a significant expense for a sandwich; one that comes without a side, any ambiance or even a white tablecloth to soak up some of the grease dripping from it.

How does one begin to calculate whether the Pepito de Iberico is worth $20? I wanted to figure it out.

Trust me, I understand that calculating value is not so simple, particularly when food is concerned. It’s one thing to tally food costs, plus operating expenses and standard markup, and determine whether you are being gouged at the cash register or not. It’s another thing to determine whether you feel satisfied gastronomically and emotionally with your purchase — that you don’t feel something akin to eater’s regret. I’m more interested in the latter calculation.

By the time I unwrapped the sandwich at my desk, the ficelle roll was slathered in a thin layer of oil, probably from the broken aioli, as if this bread were the bronzed leg of some beach bunny with a fresh application of Hawaiian Tropic. What’s more, the fatty edge of the seared Iberico pork peeked out from underneath the roll; the meat shared its bready fox hole with exquisite slices of dry-cured, well-marbled Serrano ham. As much as I understand intellectually that fat equals flavor, I have to admit that I gazed upon my lunch with the same feeling that an angioplasty patient must have when staring at a 48-ounce porterhouse: a combination of sheer unrestrained desire, and fear.

Biting into the sandwich provides the kind of tooth-tingling satisfaction that can only come from good, crusty bread. The rolls, from Panorama Bakery in Alexandria, are, in a word, superb. The filling stuffed into that roll, however, feels burdened by time and inattention: The aioli has been mostly reduced to oil; the Iberico pork has hardened into something cold and chewy; and the peppers have been roasted into a blackened, undistinguished mush, barely able to hold their original form. The caramelized onions are MIA.

The flavors combine into something undeniably savory, porcine, salty and wicked sloppy. It’s a posse of sweaty teenagers, drunk and sunburned, taking Daddy’s speed boat out for an afternoon joy ride on the lake. For my $20, I was looking for something more sleek and yachtlike. Is that asking too much from the most expensive street food in Washington?