Trade restrictions between several Mexican states and the US mean many of the best ingredients don’t make their way across the border. When I saw the local avocados in the Mexican state of Yucatan, a hot, humid region located in the south of the country, I didn’t think they were avocados. Some were the size of small melons, others the size of a large mango, three to five times the size of a Hass avocado. Perhaps these were another exotic Mexican fruit that coincidentally had the scaly green...