If you have the time, bring the fish to room temperature for 45 minutes before cooking it.
Preheat the oven to 300˚F (see note at the bottom).
Season the fish fillets with salt and pepper.
4 ounce cod, 1/4 tsp salt, 1/8 tsp pepper
Heat a large oven-safe fry pan (I like cast iron) over medium high heat. Add half the oil. (see note at the bottom if you do not have an oven-safe pan).
3 tbsp olive oil
Add the chopped garlic and cook for 10-15 seconds. Add the tomatoes and cook for 1 minute.
3 cloves garlic, 300 grams cherry tomato
Add the olives and red pepper flakes or chili pepper. Cook for an additional 5 minutes. Remove this mixture from the pan to a heat-proof bowl and set aside.
⅓ cup olives, ½ tsp red chili flakes
Return the pan to the stovetop over high heat and add the remainder of the oil. Add the fish to the pan, flesh side down (if there is skin on the fish). Sear the fish on one side for 2-3 minutes. Flip the fish to the second side and cook for 1-2 minutes. Add the tomato mixture back to the pan and place the pan in the oven for 10 minutes or until the fish flakes. Serve hot.