In a large bowl, whisk cornmeal, 1 1/2 cups of flour, sugar, baking powder, baking soda, onion powder, and cayenne.
With the large holes of a box grater, shred the butter over top of flour mixture, stopping 2 or 3 times to toss flour over the butter to prevent clumping.
Stir until combined, breaking up any large clumps.
Add buttermilk and stir until just moistened.
Turn dough onto a lightly floured surface and knead briefly with floured hands just until the dough forms a ball.
Divide into 2 equal pieces and press each into a thick disk.
Wrap each loosely in plastic wrap or parchment and freeze for 10 minutes. Note: Do not freeze for longer, or dough will be too stiff to roll.
Pat the hot dogs dry with a paper towel and stick a skewer into each, about 2-3 inches.
On a large plate, add remaining 1/3 cup of flour.
In a wide, shallow bowl, lightly beat egg whites.
Remove 1 disk of dough from the freezer and transfer to a lightly floured surface.
Using a lightly floured roller, roll into a 13-inch wide oval, only a scant 1/4 inch thick.
Cut into about 4 strips that will wrap around the hot dogs vertically, about 3 inches wide and 4.5 inches tall, depending on the size of the hot dogs.
Dip a hot dog in the flour, shaking off excess, then dip in the egg whites.
Using moist hands, wrap the hot dog with dough, gently pushing the seam together to seal.
Repeat by dipping and wrapping 3 more hot dogs.
Pinch off excess dough from ends to completely cover the tip and leave a scant 1/4 inch of hot dog exposed at the skewer end.
Repeat the process with remaining disk of dough and 4 more hot dogs.
Lightly spray air fryer basket with oil, then place corn dogs into the air fryer (leave space between the corn dogs).
Cook at 370°F/190°C for about 10 minutes, flipping halfway through, until crusts are golden brown.
Notes
Tips:
Remoisten hands between wrapping each hot dog or else the crust becomes too crumbly as you are trying to wrap it around. The moistness ensures that it stays pliable.
I used coffee stir sticks for the skewers and they worked perfectly!