Clean the leek. To do so, cut most of the green part as well as the bottom end. Peel some of the outer leaves off and wash it carefully, making sure that there is no trace of sand or soil remaining. Cut it into big pieces. Peel the carrots and cut them into big pieces as well.
Boil the red scorpionfish together with the leek, carrot and some salt. It should be ready after 12 minutes. Strain it and let it cool down on a plate.
Preheat your oven to 225ºC.
As soon as the fish is cool enough to hold with your hands, remove its scales and bones. Then, crumble the flesh into small bits.
Whisk the eggs in a bowl and add cream, tomato sauce and the crumbled fish. Add some pepper and salt and mix everything together with a fork.
Butter the metallic baking mold and sprinkle some thin breadcrumbs inside.
Pour the mixture into the metallic baking mold. Take the bigger baking dish and add some hot water. Then, place the metallic baking mold inside, so that it looks like an island surrounded by water. It doesn't need to be sinking in water, just make sure that the water covers half of the mold’s height. This technique is called “Baño María” and you will probably see it in various recipes.
Bake in the oven for about an hour and fifteen minutes. You will know that is ready by poking a fork inside the cake. If you remove the fork and it’s clean, it means that it is ready. If it is dirty, just keep it in the oven a few more minutes. Your loaf should be smooth and soft, with a pate-like texture.
Once it is ready, let it cool down, as this dish is commonly served cold. We suggest serving it with some mayonnaise.