Cut the tomatoes into ¼” slices.
In one large mixing bowl whisk together the buttermilk, egg and hot sauce. In another medium mixing bowl whisk together the cornmeal and flour then season with salt and pepper.
Add the tomatoes to the buttermilk mixture and let sit for about 10 minutes.
Add enough oil to a large cast iron skillet to fill 1” up the side of the pan. Heat the oil to 375ºF.
Working in batches, add tomatoes to the cornmeal batter and coat on both sides, pressing gently to adhere the cornmeal.
Shake excess batter off the tomatoes and add to the skillet, frying until golden brown on both sides, about 3 to 4 minutes total.
Remove to a paper towel lined plate to drain. Repeat with the remaining tomatoes until all have been fried.