Whisk cornmeal, 1 cup of flour, baking powder, sugar, salt, baking soda, and cayenne together in larger bowl.
In separate bowl, whisk buttermilk and eggs together. Slowly whisk the buttermilk mixture into cornmeal mixture until combined. Let batter site at room temperature until needed; it will thicken slightly.
Meanwhile, heat oil in Dutch oven over medium-high heat to 350°F/175°C
Set wire rack in rimmed baking sheet. Thread hot dogs onto wooden skewers. Spread remaining 1/2 cup flour into shallow dish. Dredge hot dogs in flour, brushing off excess.
Just before oil is hot, stir batter to recombine. Transfer half of batter to tall drinking glass.
Working with 1 hot dog at a time, submerge in batter using skewer as handle, and twirl to coat completely.
Remove hot dog from batter allowing excess batter to drip back into glass, and add to hot oil; repeat immediately with 3 more hot dogs.
Fry hot dogs, turning occasionally with tongs, until deep golden, 4-6 minutes; transfer to wire rack. Repeat with remaining batter and hot dogs, adjusting heat as needed to maintain temperature.
Notes
Do not use stone-ground or coarsely ground cornmeal. Quaker cornmeal should work fine.
Hot dogs come in a variety of package sizes. You will probably have enough batter to make 12 hot dogs, if desired.