Portland Mercado, 7238 SE Foster Road, portlandmercado.org. Lunch and dinner daily.
This Oaxacan cart's tlayuda ($13 for veggie, $15 for meat) is a tostada to end all tostadas—big as a pizza and eaten either by slicing it or ripping it apart like a predatory dinosaur. The baked corn tortilla is topped with a layer of spicy black beans, a pizza sauce made of protein that serves as glue for all manner of delicious things: chorizo or other meat, quesos both fresco and Oaxaca, salsa, cabbage, veggies, onions and a little bit of chicharron. It is meant to heartily serve two, but a feat of will frightening to imagine can allow a singleton to finish it off.