In a bowl, combine the buttermilk with 1 tablespoon of the Essence. Add the oysters and marinate for 5 minutes. In a shallow dish, combine the masa harina and flour with 1 tablespoon of the Essence.
In a medium, heavy pot with high sides, heat the oil to 350 degrees F.
Dredge the oysters in the flour mixture and shake the pieces in a strainer to remove any excess. Carefully add to the hot oil in batches, and cook, turning occasionally, until golden on all sides, 2 to 3 minutes. With a slotted spoon remove and drain on a paper towels. Season lightly with the remaining teaspoon of Essence.