Walking the aisles of Mercado de San Juan amounts to a Mexican culinary immersion. There are prickly pears from the northern desert, insects from the center valleys, seafood from the coasts, and pine­apples and papayas from the tropics. The market brims with people, every step suffused with the aromas of spices and mole pastes.

But walk deeper, and the true taste of Mexico City emerges. The market, open since 1955, also is home to clusters of fondas, or small restaurants. And tucked into the farthest reaches of the market is one of the oldest, Fonda Caballero, a stall of white tile counters and an open kitchen.

On this day, we’d come for their green enchiladas with chicken and cheese, a dish that—like the market itself—offers a taste of so much that makes Mexican cooking amazing.

Today, Fonda Caballero is run by the Caballero brothers, though the business dates to the opening of the market itself. That’s when their father founded it, doing the cooking and serving entirely himself for nearly his whole life.

The brothers’ recipes reflect lessons from their father, but also are drawn from their own inspiration. Breakfast and lunch are hearty affairs—huevos rancheros, pork ribs with salsa verde, chicken with mushrooms and cream, picadillo with rice and the all-time favorite enchiladas.

Corn tortillas are filled with chicken or topped with a fried egg covered with salsa, cheese, sour cream, chopped onion and cilantro. Each bite balanced—the starchy sweetness of fresh tortillas against the mild spice of serrano chili, the tangy brightness of tomatillo awash in the creamy yet light cheese and sour cream. Onion and cilantro on top add elements of herby, tangy freshness that wrap up the whole dish.

Though every element was wonderful, the Caballeros’ green chili-­tomatillo sauce truly set these enchiladas apart. Thankfully, they shared their secret: chicken broth! This was a revelation to us; we’d never considered using a meaty broth as the basis for a salsa, but it was the perfect savory foil to the fresh brightness and heat of the other ingredients. A taste experience, indeed!