It is particularly popular in the Salamanca and Ávila areas of Spain.
The filling is a mixture of ground pork loin, chorizo sausage pieces and hard-boiled eggs. Variations now use bacon, ham, even chicken. The dough is made from flour, yeast and water. It is cooked by baking.
It is made year-round, but in Salamanca, it is traditional on the day of the year called “Monday of the Waters” (“Lunes de Aguas.”)
During Lent, prostitutes were made to stay on the other side of the Tormes River, so as not to tempt people. On this day at the end of Lent, they got to come back. Hornazo was served as part of the celebration of their return. “Aguas” is similar to the word for “enagua” (meaning “petticoat”), so some think it was a double play on words for the women.