Heat the olive oil in a skillet over medium heat.
Season the cod fillets with salt and black pepper.
Add the cod fillets to the skillet and cook for 4-5 minutes on each side until golden brown.
Remove the cod fillets from the skillet and set aside.
In the same skillet, add the minced garlic and sauté for about 30 seconds.
Pour in the crushed tomatoes and stir in the lemon juice.
Bring the sauce to a simmer and reduce for 5 minutes.
Add the unsalted butter, stirring until melted and integrated into the sauce.
Return the cod fillets to the skillet, spooning sauce over them.
Garnish with fresh parsley before serving.