In a bowl whisk together your egg, mayo, mustard, cornstarch and flour and ½ teaspoon of the kosher salt.
1 egg, 1 tablespoon mayonnaise, 1 tablespoon dijon mustard, 1 tablespoon cornstarch, 1 tablespoon flour
In a food processor pulse your panko breadcrumbs a bit just to get them a little finer.
2 cups panko breadcrumbs
Combine the breadcrumbs with the paprika and remaining salt.
1/4 teaspoon paprika, 1 teaspoon kosher salt
Heat about an inch of oil in a large skillet over medium high heat.
Light oil for frying
Dredge the filets in the wet mixture then in the dry and set aside.
4 skinless cod filets
Once all the filets are breaded add them to the oil, careful not to overcrowd.
Fry them about 3-4 minutes per side until crispy golden brown on each side.
Meanwhile make your tartar sauce.
Combine the mayo, relish, sugar and onion.
1 cup mayonnaise, 2 teaspoons dill relish, 1 teaspoon sugar, 3 teaspoons finely chopped white onion
Set on a wire rack or paper towel lined plate to drain any excess grease
To assemble your sandwiches place a slice of cheese on the bottom of each bun and top with a hot filet.
4 slices of American cheese, 4 soft brioche or potato buns
Spoon your homemade tartar sauce on top of each sandwich and top with the top bun.
Serve!