Preheat oven to 425. Toss potatoes with the olive oil, salt, garlic powder, and parsley. Spread out, cut side down, on a parchment lined baking sheet. Roast for 10 mins.
Meanwhile, add the egg to a shallow bowl and beat with a fork. Add almond flour, salt, onion powder, and garlic powder to a separate shallow bowl and mix well. Pat your fish dry with a paper towel.
Heat the 1 tbsp olive or avocado oil + 1 tbsp ghee in a skillet over medium heat. Dip each piece of cod into the egg to coat, then into the almond flour mixture to coat. Place into the pan and cook for 2-3 minutes each side until browned.
Take the potatoes out of the oven and reduce the oven temperature to 400. Push the potatoes aside on the pan, making room in the middle for the fish filets. Add the fish to the pan, then bake for an additional 15-20 minutes until the fish flakes when cut and the potatoes are cooked through and crispy.
Combine all tartar sauce ingredients and mix well. Can be made 1-2 days ahead of time and will keep well in the fridge for 3-4 days.
Top the fish with the tartar sauce. The potatoes are great with the sauce, too! Enjoy!