Tyler Florence has a recipe on the Food Network and it is fantastic! I've made it over and over again..
Ingredients
1 cup stone-ground cornmeal
1 cup all-purpose flour
1 tablespoon garlic powder
Pinch cayenne
1 1/2 cups buttermilk
Kosher salt and freshly ground black pepper
4 large unripe tomatoes, cut into 1/2-inch thick slices, ends removed
1/2 cup vegetable oil
1 tablespoon unsalted butter
Hot pepper sauce, for serving
Lemon wedges, for serving
Directions
In a large bowl, combine the cornmeal, flour, garlic powder, and cayenne together. Pour the buttermilk into a separate bowl and season with salt and pepper. Dip the tomatoes in the buttermilk and then dredge them in the cornmeal mixture, coating both sides well.
Place a large cast iron skillet over medium heat and coat with the oil. When the oil is hot, pan-fry the tomatoes (in batches if necessary) until golden brown and crispy on both sides, about 3 to 4 minutes on each side. Carefully remove the tomatoes and drain on paper towels. Serve with hot pepper sauce and lemon.