How to Make It
Pour oil 2 inches deep into a 14-inch deep cast-iron skillet or large Dutch oven. Heat oil over medium-high to 350°F.
While oil heats, thread each hot dog onto skewer vertically down center. Starting at the top, slice into hot dog just until it reaches the center and hits skewer. Run the knife around while twisting hot dog to create a spiral all the way down hot dog with each slice about 1/4 to 1/2 -inch thickness. Slightly spread segments to create a spiral shape down skewer.
Stir together cornmeal, flour, baking powder, sugar, salt, and pepper in a medium bowl or large measuring cup. Add eggs and milk; stir until well combined. Pour batter into a tall glass.
Dip skewered hot dog into batter to coat well. Keep segments separated and be sure batter coats each section of the hot dog, allowing excess to drip off. Fry corn dogs, turning often, until golden brown and batter is cooked through, 1 1/2 to 2 minutes. Drain on paper towels; serve immediately with ketchup and mustard.