Final answer:
Pozole is the dish that is a specialty of the Mexican Plains region, a traditional hominy-based stew with a rich history dating back to pre-Columbian times.
Step-by-step explanation:
The specialty dish of the Mexican Plains region of Mexico is Pozole. This traditional soup or stew is made mainly from hominy, with meat (typically pork), and can be seasoned and garnished with shredded lettuce or cabbage, chili peppers, onion, garlic, radishes, avocado, salsa or limes. Pozole is a dish with a deep historical lineage, dating back to the pre-Columbian era and was significant in ritual practices. The state of Guerrero is particularly famous for its pozole, which is commonly enjoyed for celebrations and holidays.