Soak the green tomato slices in the buttermilk for at least 30 minutes at room temperature.
Cook the bacon and set it aside on paper towels to drain.
Mix the masa harina, cornmeal and creole seasoning and place it in a wide and shallow dish.
Pull the tomato slices out of the buttermilk and dredge them in the cornmeal mixture.
Fry the tomato slices in oil over medium heat until golden brown on both sides, about 3-4 minute per side and set aside to drain on paper towels.
Heat a pan over medium heat.
Butter the outside side of each slice of bread, place one slice in a pan buttered side down, spread on half of the cheese, then top with the the fried green tomato slices and bacon followed by the remaining cheese and slice of bread, buttered side up.
Cook until golden brown on both sides and the cheese is melted, about 2-4 minutes per side.