Thaw and dry the cod fillets. Cut the potatoes into fries and place in a bowl of cold water to soak for 1-2 hours.
Mix ½ cup flour, 1 Tablespoon of sugar, 1 teaspoon of fine grind sea salt, and ½ teaspoon of pepper in a shallow breading dish.
Mix 1 cup breadcrumbs with 2 teaspoons of sugar, 1 teaspoon of fine grind sea salt, and ½ teaspoon pepper in a second shallow breading dish.
Whisk ½ cup cold beer or water with 1 egg in a third shallow breading dish. Sift ¼ cup of flour over the top of the liquid and fold the flour into the liquid. Don't whisk it in or you will develop the gluten in the flour. Repeat with another ¼ cup flour. Add the remaining ¼ cup of flour and fold into the liquid until your batter is the consistency of a thick pancake batter.
Line a tray with parchment. Coat each cod fillet with the flour and then coat in the wet batter. Let any excess wet batter drip off and place the fillet into the breadcrumb mixture and spoon the breading over the fish so it is completely covered. Let sit in the breadcrumb mixture while you coat the second fillet with flour and the wet batter. Remove the fish from the breadcrumb mixture and set on parchment lined tray. Repeat for all of the fish fillets. Place the tray in the freezer for 1-2 hours.
When the fish is frozen, preheat the air fryer on its hottest setting for 10 minutes. Drain and dry the fries. Spritz the fries with oil and lightly season with salt and pepper if desired.
Place the fries in the air fryer and air fry on 400℉/200℃ for about 15 minutes. Gently flip the fries mid way through. If you have the ability to create a second level of air frying, add the rack when the fries have 5 minutes left so you preheat the rack.
Spritz the fish fillets with oil on both sides. Place the fish fillets next to the fries or on the second layer and AC at 400℉/200℃ for 8 minutes. Flip the fish and AC another 4 minutes. The number of fish fillets and fries you can do at once depends on your air fryer. In the Ninja Foodi Pressure Cooker & Air Crisper, I can do 3 servings at a time.
Serve & Enjoy!