The hotel we stayed in included a hot buffet breakfast. Most of the items contained meat, but at the end of the buffet there was a woman who made eggs to order. So we took advantage of that. A Yucatecan egg dish, Huevos Motulenos, is easily converted into vegetarian, pictured above. Just ask for them without ham. The dish contains a crispy corn tortilla topped with refried black beans, fried eggs, tomato sauce, cheese (in this case both Manchego and Queso Fresco) and peas. Also served with this dish were fried plantains.
Another thing we took advantage of during breakfast is the wonderful fruit grown in the Yucatan. For instance, papaya is available there year round, and it is more sweet and juicy than any I've had in the States.