Piedras (Mexican pastry “rocks” or “stones”)

“Piedras” (meaning “rocks” or “stones”) are served at Mi Tierra Restaurant & Bakery in San Antonio, described as “a raisin pecan cookie with sweet pink icing.” Piedras are often made from day-old bread, so the “rock” or “stone” is indeed hard.
 
“Piedras” have been cited in print in Texas newspapers since at least the 1940s.
 
   
Mexico Connect
Las Panaderías:
Mexico’s Irresistible Bakeries
Karen Hursh Graber
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The Mexicans have named their baked goods as whimsically as the Italians have named their pastas. Conchas (shells), orejas (ears), cuernos (horns), and cochinitos (little pigs) are only a few favorites. Care to try something different? How about bigotes (moustaches), trenzas (braids), or corbatas (neckties.) For the more adventurous, there are the somewhat aggressively named picones (jabbers) and piedras (stones.)
   
Mi Tierra Restaurant & Bakery (San Antonio, TX)
Piedra
a raisin pecan cookie with sweet pink icing. 
 
12 November 1949, San Antonio (TX) Light, pg. 2, col. 1:
Jose Bernal Moreno has been baking pan de dulce in San Antonio for 53 years.
 
He came here shortly before the turn of the century, after learning the art of pastry making in Monterrey. he recalls:
 
‘There were times when I went out and cut mesquite wood for my oven.”
 
Moreno is a good hand at all varieties of pan de dulce, among them pan de huevos (egg buns) and the rock-shaped pan de piedras.
 
7 July 1977, San Antonio (TX) Light, “Pan Dulce: S.A. Has the Best” by Ed Castillo, pg. 2B, col. 3:
Mi Tierra alone baked more than 30 varieties of the sweet bread which is so eagerly sought by local residents from all quadrants of the city.
 
Some of the more popular pieces of pan dulce are the “pan de huevo” (egg bread); “polvoron” (comes from the word “polvo,” or dust, which is the fine sugar sprinkled over it); “empanada” (Pg. 3B, col. 3—ed.) (turnover, usually filled with sweet potato, apple or pineapple); “Ricardos” (named after the head baker, bread topped with glazed sugar and nuts).
 
Others: “Florecita” (little flower); “piedra” (rock); “cuerno” (horn); “caracol” (snail); “concha” (shell); “perla” (pearl); “chilindrinas” (the bright ones), and “semita de anis” (anise bun). There are many others.
     
MySA.com
A glossary of popular pan dulce (June 9, 1999)
Hector Saldana   San Antonio Express-News
Food Page 1F (356 Words)
   
Campechana - flaky, layered pastry with sugary glaze
Empanada - fruit-filled turnover, usually with pumpkin filling
Marranito - little brown piglet-shaped molasses cookie
Pan de huevo - slightly sweet, dense yeast-dough bread flavored with vanilla and stick cinnamon. Often called conchas for its shell pattern
Cuernito - sugary, cinnamon horn of pan de huevo
Piedra - cookie made from day-old bread with pink icing
Oreja de wey - rolled French pastry shaped… 
 
30 January 2002, Los Angeles (CA) Times, “Delicate pan dulce, fragrant fresh masa and beautiful plates all can be found on one short stretch in East L.A.” by Barbara Hansen, pg. H1:
Try piedras (rocks), big cookie-breads that are dark and rough-looking but tender and sweet when you bite into them. They’re made with corn flour.
 
Google Books
Cooking with Texas Highways
by Nola McKey
Austin, TX: University of Texas Press
2005
Pg. 5 (Name That Pan Dulce!):
piedras: Small, sugar-coated hard breads that look like small rocks.
 
13 April 2005, Los Angeles (CA) Times, “A new world of panaderias; Pan dulce has gone pan-Latin” by Barbara Hansen, pg. F1:
This old-time bakery has a glorious selection of pan dulce, including flat, crisp pan tostado, sweet empanadas, monjas (nuns), piedras (rocks) and panque,
 
Chowhound - Texas
The West Hildebrand Bedoy’s still makes, on-site, some of the best flour tortillas in San Antonio. Even they have cut back on the lard over the years, but they still add enough. Their corn tortillas are good, too, but Bandera Molino has the edge in that category. Bedoy’s polvorones (cinnamon- and sugar-topped crumbly cookies—polvo means dust) are still excellent. So is their yeast-based pan dulce—like the cuernos (little horns) and the rolls that look like sugary croissants. Their campechanas (a long rectangle of thin layers of glazed, crunchy pastry) and empanadas de camote [camote means sweet potato], two traditional varieties of pan dulce, were very tasty, too. But the quality of their other pastries can be inconsistent. On my last visit, the marranitos (pig-shaped gingerbread-like sweets) and the piedras were hard. Piedras means rocks, but they’re not supposed to be that hard! Of course, given the very low prices ($2 for 5 pieces of pan dulce), I didn’t really mind.
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MPH Aug 24, 2006 05:19AM