In a deep-fryer, preheat oil to 350 degrees F.
Season tomatoes, on both sides, with salt and pepper. Place flour and garlic powder in a shallow dish. In another shallow dish, beat eggs with the milk. In another dish, mix bread crumbs with cayenne and paprika. Dredge tomatoes through the flour, then the eggs, and then through the bread crumbs. Add only a few pieces to the fryer at a time, so they can cook evenly, about 2 to 3 minutes. Drain on paper towels and serve with Buttermilk Dipping Sauce:
In a small saucepan over medium heat, combine the apple cider and brown sugar. Allow to reduce until thick and syrupy. Remove from heat and allow to cool.
In a medium bowl, add buttermilk, mayonnaise, BBQ sauce and lime juice and whisk well. Add in the scallions and the apple cider mixture. Cover and refrigerate until ready to serve with Fried Green Tomatoes.