In a medium bowl, whisk together buttermilk, cornmeal, flours, and salt until smooth. Whisk in water 1 tablespoon at a time until mixture is the consistency of thin pancake batter.
In a Dutch oven, pour oil to a depth of 1 inch, and heat over medium heat until a deep-fry thermometer registers 330°.
Dip tomatoes in batter to coat, letting excess drip off. Fry tomatoes until golden brown, 4 to 5 minutes, turning halfway through. Let drain on paper towels; sprinkle with additional salt while still warm. Serve immediately.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/irondale-cafe-fried-green-tomatoes-recipe/