In a medium-sized shallow dish, combine melted butter, garlic powder and freshly squeezed lemon juice. Set aside.
In another medium-sized shallow dish, combine Panko breadcrumbs and the rest of the dry seasonings. Mix well.
Gently coat each filet with the butter mixture and then with the Panko mixture, taking care to coat with as much Panko coating as possible.
Heat 1/2 tablespoons olive oil over high heat in a non-stick, oven-safe skillet. Once oil and pan are hot, add the Panko-coated fillets. Pour the remaining lemon-butter mixture over and around the fish and carefully pat as much of the remaining Panko coating on the fish as possible. Throw in a few thinly sliced lemons to brown as well (if you wish, for garnish and added lemon flavor). Heat on high until the bottom side turns golden brown and the butter starts to brown, about 2-4 minutes. Careful not to burn the butter or the fish.
Once the bottom side is golden brown, carefully flip the fillets over and place the skillet into the oven. Bake until the fish breaks apart easily with the twist of a fork, about 10-12 minutes, depending on the size of the fillets. Careful not to overcook at this point.