Cut the chicken breasts in half horizontally to make 4 thin cutlets. Place cutlets between 2 pieces of heavy-duty plastic wrap and pound to 1/8-inch thick with a mallet or heavy skillet. Season the chicken with 1 tsp salt and 1/2 tsp each pepper and paprika.
Heat about 2 inches peanut oil in a heavy bottomed pot over medium heat until a deep fry thermometer registers 325 degrees. Meanwhile, whisk the effs, milk and 2 TBSP water in a baking dish. Whisk both flours, malted milk powder, powder sugar, baking soda, dry mustard, 1/2 tsp paprika and 1 tsp salt and pepper in another dish. Toss the pickle slices, juice and vinegar in a bowl and set it aside.
Working in batches dip the chicken in the egg mixture, turning to coat, then dredge in the flour mixture and shake off excess. Fry the chicken in the hot oil until golden brown, about 4 minutes, adjusting heat as needed. Drain on paper towels.
Heat a large skillet over medium high heat. Spread the cut sides of the bun with butter and lightly toast in the skillet, spread with more butter. Put 2 pickle slices on each bun bottom, top with chicken and other bun.