The recipe for a simple, yet deliciously hearty soup: Fish broth with garlic crostini!
The cooking time will depend on the size of the fish you are using. If you are using bigger fish, I suggest you cut them in half (horizontally) and remove the tail parts after cooking them for 30 minutes, so you can eat this fish later. Keep simmering the stock with the heads (which can be discarded later). If your fish was small to begin with, it will melt away in the stock, so do not worry about it.