Pat the halibut filets dry with a paper towel. Season the flesh side with kosher salt and black pepper. In a small bowl, mix together the mayonnaise, parsley, and garlic. Spread in an even layer on top of the halibut filets (flesh side). Sprinkle the panko on top.
Preheat air fryer to 400 degrees Fahrenheit. Carefully place the halibut fillets inside the air fryer basket with space between them.
Air fry for 7-8 minutes at 400F or until an internal temperature of 130-135 degrees Fahrenheit is reached for medium temperature.
If you'd prefer the fish be well-done, cook to a 145 F internal temperature, about 10 minutes total.
Notes
To cook this in a regular oven - Bake at 425F for about 15 minutes.
For a toaster oven air fryer - Cooking times may take 1-2 minutes longer.
To defrost frozen halibut, place it in the fridge overnight, or defrost quickly in a sealed bag placed in cold water for about 30 minutes.
These times worked with a halibut fillet that was about 1" thickness. Cooking times will be longer for a thicker fillet.
Halibut is well done at 145 degrees Fahrenheit, but that is the USDA recommendation for cooking fish. Please cook to to your own preference! The mayonnaise gives this some extra moisture. I personally prefer medium (around 130-135F)
Use gluten free panko for a gluten free meal. Skip the added salt and consider homemade breadcrumbs for low sodium.