“What was here has given birth” t o what Texans eat today, said Mr. Vasquez, noting that his ancestors were the ones doing the first hot-stone-and-pit cooking , often with unwanted cuts of meat like the cow heads left to them by Spanish.

The park has just converted 50 acres to farmland, which Mr. Vasquez hopes to help plant with native species, many of which are highlighted in Mr. Medrano’s new book. (It also includes a recipe from Mr. Vasquez’s mother for bison with blackberries and pecans, along with family recipes from the Texas artist César Martínez and the El Paso-born chef Rico Torres, of the modern Mexican restaurant Mixtli in San Antonio.)

This rich and living history is the reason San Antonio was awarded the rare City of Gastronomy designation in 2017 by Unesco. The city tapped Mr. Medrano to help create its application.

The recognition is a remarkable turnabout. The missions, after all, are only a few miles south of the plaza where Texas Mexican women were blocked from selling carne con chile from open-air stands in the early 20th century, while the dish itself was co-opted into chili. This is also where Otis Farnsworth, a Chicago transplant, opened his highly successful Original Mexican Restaurant, one of the first places serving what would become known as Tex-Mex.

Today, Farnsworth’s restaurant might be called out for cultural appropriation, or what Mr. Medrano calls “cultural poaching.” And Mr. Medrano does get angry at the lack of respect for his culture, the many ways in which Mexican-Americans have been wronged throughout history.

But he is generally driven by love for their cuisine, which delights him every time he sees a tortilla puff on a griddle, or catches the mingled scent of black pepper and cumin.

“We need to share the beauty of the food,” Mr. Medrano said, “and if we do, the world will be more beautiful.”