“Pambazo” is a dark bread, from the Spanish “pan bajo,” or “bread eaten by the poor.” In Vera Cruz (Mexico), “pambazo” is also a sandwich filled with potatoes and chorizo, and dipped in red chile sauce. “Pambazo” is cited in English from at least 1904.
 
Restaurants in Houston and in San Antonio have offered “pambazo” sandwiches on their menus.
   
     
Wikipedia: Pambazo
Pambazo is a Mexican dish or antojito (very similar to the torta made from special bread dipped in a red guajillo pepper sauce and filled with a guiso (filling) like papas con chorizo (potatoes with chorizo), frijoles refritos (refried beans) or longaniza. It is then garnished with shredded lettuce, salsa (sauce), cream and queso fresco (fresh cheese).
 
Originally, this is the classic recipe, but as the dish spread through the states it suffered some changes. The bread used for pambazos is white and lacks a crispy crust, and it is called pambazo as the dish. This particular bread is made of flour, lard, eggs, and its more resistant than a bolillo. This characteristic allows marinating.
 
Steps for preparing a pambazo
Dip the bread lightly in the guajillo sauce.
Fry the pambazo bread until it is crunchy on both sides.
Cut the pambazo bread in half, fill and garnish.
Serve it. 
 
Houston Press - Eating Our Words blog
The Carnicería Connoisseur: A Glossary
Thu Nov 08, 2007 at 11:50:10 AM
(...)
Torta Pambazo or Pambazo – a sandwich on a chile-dipped bun.
     
Romero’s Las Brazas (Houston, TX)
Pambazo Chilango—Mexican bread brushed with red salsa, grilled and stuffed with chorizo, potato, Mexican cheese, lettuce & s. cream…...........................4.99
     
Flour Power Cafe (San Antonio, TX)
This menu is fond of meat: the pambazo sandwich features ham, turkey, shredded pork, and refried beans. 
 
Emerils.com
PAMBAZO (VERA CRUZ SANDWICH)
from Emeril Live EM1C51
 
Ingredients needed:
For the Bolillo:
1 envelope (1/4-ounce) active dry yeast
3 tablespoons sugar
2 cups warm water (about 110 degrees F)
5 cups flour
1 tablespoon butter, at room temperature
1 1/2 tablespoons salt
1/2 teaspoon ground cinnamon
For the sandwich:
1 cup mayonnaise
2 pounds roasted pork butt, shredded
1 cup thinly sliced red onions
1 1/2 cups peeled, seeded and chopped tomatoes
2 large avocados, peeled, sliced 1/4-inch thick and seasoned
3 cups refried beans, hot
1 pound thinly sliced cheese (...)
 
25 September 1904, Mexican Herald, pg. 9, col. 2:
Peon Restaurant of City of Mexico:
“Square Meals” For From Two Cents Up
(...)
(Col. 3—ed.)
A loaf of bread, called “pambazo” or rather “pan bozo” made of common flour, and about three inches long, is cut half lengthwise. This loaf is hollow. In the cavity is place (sic) a tablespoonful of this stew: a spoonful of chile sauce poured over it; the other half loaf placed on top, and there you are for three centavos. No Anglo-Saxon, with eyes and an imagination—unless he is nearly starved—can bolt that combination. 
   
Google Books
Some Examples of the New World
by Michael John Doudoroff
Dept. of Modern European Languages
1964
Pg. 66:
pambazo from pan bajo, the cheapest king of bread. 
 
Google Books
Mexico: Her Daily & Festive Breads
by Barbara Howland Taylor
Claremont, CA: Creative Press
1969
Pg.  94:
pambazo, dark bread.
 
Google Books
The Collected Stories of Amado Muro
by Amado Muro
Austin, TX: Thorp Springs Press
1979
Pg.  46:
After ordering pambazo, Don Lupe had the mariachis sing Veracruz songs filled with moonlight and langorous winds.
 
7 March 1991, Los Angeles (CA) Times, pg. H43:
Next to them are piles of golden egg-yolk bread, wheat-flour powder cookies, and pambazo sandwiches (fried in oil until crisp and stuffed with diced potato, ... 
 
Google Books
A Cook’s Tour of Mexico
by Nancy Zaslavsky
New York, NY: St. Martin’s Press
1995
Pg.  182:
Pambazo. A Veracruz sandwich is a pambazo, sometimes bambaso (as at the bakery, Panaderia y Pasteleria Colon). The difference is the roll (like Puebla and Cholula’s cemita) and again, both roll and sandwich have the same name. This time around, it’s a soft hamburger bun dusted with flour or sprinkled with sesame seeds. Pambazos, found all over town at stand-at-the-counter-and-eat places, are first spread with black beans, then stuffed with the usual Torta stuffings (page 120). Small wrapped versions are for sale in bakeries.
   
21 November 1996, Los Angeles (CA) Times, “City Tacos” by Charles Perry, pg. H7:
In effect, a pambazo is cross between a torta and an enchilada made with a roll instead of a tortilla, with a filling of mashed potatoes and chorizo.
   
Google Books
Zarela’s Veracruz: Mexico’s Simplest Cuisine
by Zarela Martinex and Anne Mendelson
Boston, MA: Houghton Mifflin
2001
Pg. 109:
Pambazos
FLOUR-DUSTED SANDWICH BUNS WITH FILLINGS
   
IF VERACRUZ HAD AN OFFICIAL SANDWICH, IT WOULD BE pambazos, also affectionately called pambacitos. They are lovely little yeast buns that you split and fill with something irresistible, like beans and chorizo. at a glance, a pambazo looks a little like a Sloppy Joe, but the resemblance ends there. Pambazos are among the best yeast rolls I’ve ever eaten, a tender and delicate contrast to the rich flavors of the fillings. They are a favorite dish at cendurias (places that serve simple supper dishes) in Xalapa and Orizaba, but hey are loved in other parts of the state as well. You can also buy the rolls at bakeries and take them home to serve with your own fillings. 
 
11 May 2001, San Antonio (TX) Express-News, Weekender, pg. 34H:
That’s true, but I don’t remember Mom ever making a sandwich quite as memorable as the Pambazo, with juicy, shredded roast pork topped with healthy slices ... 
   
14 August 2002, Tri-Valley Herald (Pleasanton, CA):
Try the huaraches or the pambazo, a sweet roll slathered with red chili sauce and filled with chorizo and potato. 
 
Forbes (November 14, 2002)
Another Mexico
Martha Rose Shulman for Saveur
(...)
Carmen also pointed out pambazos, the flour-dusted rolls used for one of her favorite Veracruzano sandwiches from childhood—itself also called pambazo, filled with puréed beans, canned sardines, thin avocado slices, pickled chipotles, lettuce and tomatoes.
   
7 February 2003, San Jose (CA) Mercury News, pg. 46:
New to Chalateco is the pambazo ($6.50), a smaller sandwich covered with mild red sauce, known as the ‘‘wet torta.’’ 
         
Google Books
Food Culture in Mexico 
by Janet Long-Solís and Luis Alberto Vargas
Westport, CT: Greenwood Press
2005
Pg. 148:
Another favorite is a hard-roll sandwich made with a Spanish-style bread roll and filled with diced potatoes fried with chorizo and chopped lettuce and flavored with chipotle chiles. This snack is known as a pambazo, a word that comes from the term pan bajo, or “bread eaten by the poor.”
 
10 June 2005, San Antonio (TX) Express-News, Weekender, pg. 36H:
The Pambazo, shredded roast pork, refried beans, avocado, tomatoes and red onions encased in French bread, was powerfully good. 
 
San Francisco Chronicle
THE COMIDA CORRIDOR
Oakland’s International Boulevard is known for its taco trucks, but also boasts plenty of places to find down-home Mexican food
Carol Ness, Chronicle Staff Writer
Wednesday, January 25, 2006
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It’s the chorizo-stuffed pambazo (big grilled sandwich) and huitlacoche huaraches (super-thick oval tortillas) from Mexico City, dispensed all day long from the busy window of La Torta Loca.
 
LA Weekly   
Ask Mr. Gold: Pambazo
By Jonathan Gold
Wednesday, September 6, 2006 - 2:00 pm
 
Dear Mr. Gold:
Pambazo. I’ve gotta have one. Any ideas?
—George, Lomita
 
Dear George:
By a pambazo, I assume that you are referring to the central Mexican snack, an evolved version of the French dip sandwich where the bread is soaked in chile sauce instead of a thin beef jus, where the pallid slices of roast beef are replaced by dollops of stew, where the sandwich in question is often fried for a bit after it has been stuffed so that it tightens into a cohesive, amalgamated mass. (The sensations of a Guadalajara-style torta ahogada, while superficially similar, seem crude by comparison.) The Los Angeles area is not rich in pambazos for some reason, but you will find an excellent version at Taqueria Vista Hermosa in the Mercado La Paloma near USC, stuffed with potatoes and spicy chorizo sausage and drizzled with cream, a sandwich that threatens to deliver its red-orange payload right down the front of your shirt. If you’re still hungry, Vista Hermosa’s freshly grilled tacos al pastor are not half bad. 3655 S. Grand Ave., Mercado La Paloma, L.A., (213) 741-1251. 
   
Vivirlatino
MON 26 Nov 2007
Still got mashed potatoes? Make taquitos
(...)
Now most Americans don’t get the carb-on-carb obsession found in many Latin American cuisines. A few good examples are: Pambazo (a Mexican antojito consisting of bread with potatoes inside and deep fried), quesadilla de papa, and the matter at hand: taquitos de papa.