Being a judge at a macaroni and cheese competition in San Francisco taught me a lot about American food. The competitors were mostly chefs, and the audience—the online tickets sold out in minutes—was soaking up the chance to be at a “Top Chef” kind of event, but more urban and cool. The judges included a food writer, an award-winning grilled-cheese-maker, and me, a cheesemonger.

We awarded the win to a chef who made mac and cheese with an aged Vermont …