Prep Hot Dogs: Dry hot dogs and skewer them. Set a wire rack over a sheet pan aside.
Make Batter: Whisk together 125g flour, 120g cornmeal, 37.5g sugar, 4g baking powder, 5g salt, 2.5g baking soda, 0.5g black pepper, and 0.5g cayenne. Mix 240g buttermilk and 2 eggs, then combine with dry ingredients.
Coat Sausages: Pour batter into a tall glass for easy dipping. Dip each sausage in batter, let excess drip off, and place on the wire rack.
Fry: Heat oil to 190°C (375°F). Fry hot dogs until golden (about 3-4 minutes). Don't overcrowd the pot.
Drain and Serve: Place fried sausage on paper towels or a clean rack. Serve with ketchup and mustard.