Rinse and slice the green tomatoes into about ¼ inch thick slices. Pat the tomatoes dry with paper towels to remove any excess moisture and set them aside.
In a shallow dish, whisk together the buttermilk, egg, and hot sauce. In a second shallow dish or bowl, add flour, cornmeal, salt, pepper, onion powder, garlic powder, smoked paprika, and cayenne pepper until combined.
Working with one tomato at a time, coat both sides of the tomato in the buttermilk mixture, then in the cornmeal mixture, shaking off any excess. Allow the breaded tomatoes to sit on the baking sheet while you heat the frying oil. This helps the breading stick to the tomatoes.
Heat oil in a 10-inch cast-iron or heavy-bottom skillet until it reaches 350°F on a deep fryer thermometer. Working in batches of 3 to 4 tomatoes at a time, carefully place the tomatoes in the hot oil and fry, flipping once, until golden brown on both sides, about 2 to 3 minutes per side. Repeat with the remaining tomato slices. Carefully transfer the fried green tomatoes to a wire rack to cool.
Serve the tomatoes warm with your favorite dipping sauce, such as our New Orleans Remoulade Sauce. Enjoy!