PIEDRAS NEGRAS, Mexico It takes all day to shlep from New York to this drab border town some 140 miles southwest of San Antonio. But for a nacho-nut like me, it was like a trip to Plymouth Rock, where the whole noble finger-food experiment began. And the time to enter the sacred precincts of Restaurante Moderno was now -- on the eve of the Super Bowl, when the nacho attains its apogee, when millions of hands reach out for a delicious mess of corn chip, melted cheese, jalapeño slices and God knows what else.

Over-the-top toppings can ruin this dish. Baroque "Mexican" versions of the nacho are all too common, with refried beans, guacamole and sour cream tossed over the chips and cheese. You might even stumble upon nachos with shrimp, chicken, beef, the Aztec corn fungus huitlacoche, sea bass, sushi and a ghastly range of bottled sauces.

This culinary confusion may be one reason prospects for the nacho seem to be softening. According to the NPD Group, a market research firm, servings of nachos in fast-food and casual restaurants dropped by 3% in each of the past two years.

My mission to Piedras Negras, then, was a search for the primeval nacho, a handmade and beautifully simple concoction, built from corn tortillas cut on the spot into triangles and fried in lard, with real cheese, not orange lava from a bottle, and plenty of pepper slices cut from whole peppers. This is what I hoped to find at the Moderno. It's certainly what any Super Bowl hero making nachos at home tomorrow should strive for.

It's a well-established ritual. American men in the millions have almost finished their preparations for the big game. They've bought a wide-screen HD television. They've paid enough attention to the records of the Seattle Seahawks and the Pittsburgh Steelers to feel confident about gaming the point spread. Now all they have to do is shop for the nachos they will bravely "cook" in their annual visit to the family kitchen.