1. Thaw the black cod.
2. Put a little oil in the pan, sauté the garlic, thyme and diced tomatoes until fragrant, and then add tomato paste, salt and black pepper for seasoning.
3. After it boils, pour it into a baking dish, put the black cod in, and then put the baking dish into the oven. Bake at 200 degrees Celsius for 15 minutes.
4. Sprinkle mozzarella cheese on top and bake for another 5 minutes. Then take it out of the oven.