Heat a large, heavy skillet over medium-high heat. Rinse any ice glaze from frozen Alaska Cod under cold water; pat dry with paper towel. Brush both sides of fillets generously with olive oil. Place cod in heated skillet and cook, uncovered, until lightly browned, moving fillets gently and adding small amounts of oil as needed to keep fillets from sticking. Without turning fillets over, cook 3/4 of the way through, about 5 to 6 minutes for frozen cod or 3 to 4 minutes for fresh/thawed fish.