Fill a large, heavy pot, Dutch oven, or deep fryer with enough oil to submerge hot dogs; heat until a deep-fry thermometer reaches 350º F (180º C) NOTE: I highly recommend using a deep-fry thermometer.
Pat the hot dogs dry with paper towels. Insert the sticks through each hot dog lengthwise, leaving enough of the stick showing to create a handle. NOTE: Make sure the hot dog and stick will fit into the pot; the corndog needs to be completely submerged in the oil.
Whisk together dry ingredients, cornmeal, flour, sugar, baking powder, and salt.
Add wet ingredients, evaporated milk, buttermilk, and oil. Whisk until well combined.
Pour batter into a tall drinking glass for easy dipping.
Dip each corndog, one at the time, straight down into the batter, and give it a little twirl to fully coat the hot dogs. Let excess drip off. After dipping, carefully hold the corn dog, partially submerged, at an angle in the hot oil for 5-7 seconds to let it seal, then drop it into the oil (this keeps them from sticking to the bottom of the pot).
Fry each dog until golden brown, about 3-4 minutes per corndog. Remove from the oil and transfer to a paper-towel-lined plate, turning to blot oil. Working in batches of 2 - 3, repeat with remaining hot dogs and batter.
Serve immediately with ketchup and yellow mustard, if desired.