What exactly is a hamburguesa estilo Monterrey? I visited the Hamburguesas Del Rio location at Avenida Constitucion 1121 Pte. Centro in Monterrey, Mexico to seek the definitive answer to that question. I had long assumed that the term described a specific Mexican-style set of garnishes, namely the shredded lettuce, chopped onion, sliced tomato, hamburger patty, slice of ham and avocado architecture seen in the photo.
But I was wrong. A couple of bites revealed that there was something altogether different about the hamburger patty itself. So I asked the man with the spatula, the intrepid hamburguesero, what went into the meat mix. Migas (bread crumbs), huevos (eggs), and garlic salt were among the ingredients he listed. I have since found recipes online that include those items as well as salsa Ingles (Worcestershire), soy sauce, and other seasonings.
Seems like the Mexican hamburger recipe is inspired by the much older and more popular
recipe for albondigas (meatballs). On the one hand, you could argue that this is a perfectly acceptable style of hamburger. But on the other hand, I have read that the busiest Carl's Jr. location on the planet is located in an upscale neighborhood of San Pedro Garza Garcia in Monterrey. So evidently, the attraction of the unbreaded hamburger isn't lost on the citizens of Monterrey. But neither have they lost their preference for the garnish style.
When you ask for a hamburguesa estilo Monterrey in Houston, you get a regular burger with the avocados and ham. I am guessing that in the post-NAFTA era, the hamburguesa estilo Monterrey has developed a split personality. In Monterrey it means a hamburger with the breading and spices served with the traditional garnishes. But in the United States, it can also mean a regular all-beef hamburger dressed with a slice of ham and avocados, Monterrey-style.