Slice the tomatoes into 1/2 inch thick slices. Lightly season both sides with sea salt and freshly cracked pepper, to taste.
Place 1/4 cup of flour in a shallow bowl.
In a separate shallow bowl add the remaining flour, cornmeal, garlic powder, paprika, and cayenne pepper. Season with some sea salt and freshly cracked pepper, to taste; mix well.
Lastly, whisk the buttermilk and egg together in a separate shallow bowl.
Heat enough oil to cover the bottom of a large skillet over medium-high heat until hot.
While the oil is heating, dredge the tomato slices first by completely coating them in the flour, then the buttermilk mixture, and finally the cornmeal mixture.
Using a fork, gently place the coated tomato slices in the HOT oil and cook for 1-2 minutes, or until golden brown.
Carefully flip the tomatoes and cook for another 1-2 minutes, or until golden brown. Side Note: Do not overcook the tomatoes or they may become mushy inside.
Remove the tomatoes to a paper towel lined plate then season with a bit of sea salt, to taste.
Place the fried green heirloom tomatoes on a serving plate and sprinkle with some fresh parsley. Serve immediately with the buttermilk ranch dressing. Enjoy!