Preheat oven to 400°F. In a shallow bowl, mix together the lemon juice, 4 tablespoon olive oil and butter. In another bowl, mix together the flour and spices.
Dip the fish in the lemon mixture then dip in the flour, shaking off any excess. (Reserve the lemon juice mixture for later)
Take the remaining lemon juice mixture and stir in the garlic and set aside.
In a large cast iron skillet, heat the remaining 1 tablespoon of olive oil over medium-high heat. Add the fish and cook for about 2 minutes on each side to brown it.
Drizzle the fish with the lemon juice and garlic mixture. Bake for about 10 minutes or until the fish flakes with a fork. Remove and top with some parsley.
Notes
Use wild cod if possible. It is healthier for you and just tastes better.
If your cod fillets vary in thickness, try to choose fillets that are of similar thickness or adjust the cooking time accordingly. Thicker fillets may need a bit more time in the oven.
Use freshly squeezed lemon juice. Never use store-bought for something where lemon is the star.
You can skip searing the cod if you want. Just add to a baking sheet or skillet and toss in the oven. You'll want to cook for an extra 4 minutes.
Leftovers will last in the fridge for 2-3 days or freezer for 1 month.