Pat the cod fillets dry with paper towels. Season with salt and pepper.
Heat the olive oil in a large skillet over medium-high heat. Add the cod fillets to the skillet and sear for 3-4 minutes per side, or until cooked through.
Remove the cod fillets from the skillet and set aside. Add the butter to the skillet and melt over medium heat. Stir in the lemon juice and parsley.
Pour the lemon butter sauce over the cod fillets and serve immediately.