Pat your cod dry with paper towels and cut it into 1-inch wide sticks.
Take out three bowls to set up your dredging station.
Add your flour into the first bowl.
Add your eggs along with the dijon mustard and lemon juice into the second bowl. Whisk them together.
Add your panko breadcrumbs, parmesan and all of the seasonings into the third bowl. Mix them together.
Dredge each fish stick in the flour first, then the egg mixture, then the panko mixture, pressing gently so it sticks.
Preheat your air fryer on 400°F for 5 minutes.
Arrange your breaded fish sticks in a single layer in the basket, leaving space between the pieces. Don't overcrowd the basket and cook in multiple batches if needed. Air fry on 400°F for 8 to 10 minutes, flipping halfway through, until golden and they reach an internal temperature of 145°F.
Let them rest for 2 to 3 minutes before serving.
Take out a bowl to mix your tartar sauce.
Add all of the ingredients for the tartar sauce into the bowl and mix everything together.
This is optional, but it's recommended that you chill the sauce in the fridge for at least 15 minutes to let the flavors meld.
Serve your fish sticks with the tartar sauce.