Coating the skewered hot dogs in flour before batter-dipping ensures the batter adheres to the hot dogs. To make coating the hot dogs easy, we transfer the batter to a tall drinking glass for even, hassle free dunking.
Set wire rack inside rimmed baking sheet. Whisk cornmeal, 1 cup flour, baking powder, baking soda, sugar, salt, and cayenne together in bowl. Whisk in buttermilk and eggs until incorporated. Place remaining 1/2 cup flour in shallow dish. Dredge hot dogs in flour and shake to remove excess. Thread hot dogs lengthwise onto eight 8-inch skewers.
Add oil to large Dutch oven until it measures about 2 inches deep and heat over medium-high heat to 350 degrees. Stir batter to recombine, then transfer half of batter to tall drinking glass. Working with one at a time, submerge hot dog in glass and twirl to coat with batter. Allow excess batter to drip back into glass and place corn dog in hot oil. Repeat immediately with 3 more hot dogs.
Fry corn dogs, turning occasionally, until golden brown, 4 to 6 minutes. Transfer to wire rack. Return oil to 350 degrees and repeat with remaining batter and hot dogs.