Preheat your oven to 325 degrees F.
Spray one 8-inch round cake pan with nonstick spray. Line the bottom with parchment paper. Spray again and set aside.
In a medium saucepan, add the water, sugar and salt. Bring the mixture to a boil, stirring occasionally to make sure the sugar dissolves completely.
While the water mixture boils, combine the chocolate chips and butter in a medium sized mixing bowl.
Pour the hot water mixture over the chocolate chips and butter. Stir until the chocolate and butter are melted and create a silky, smooth texture. Let cool for about 10 minutes before you add the eggs. We don't want to cook the eggs!
In a small bowl, whisk the eggs and vanilla. Add the egg mixture to the chocolate mixture and mix well. No beating required, just mix with a wooden spoon or spatula.
Pour the batter into the prepared pan.
Place the 8-inch cake pan in a larger baking dish. Place the baking dish on the middle rack of the oven and then pour hot water into the larger baking disk to create a "bath" for the cake. You need enough water to go half way up the side of the 8-inch cake pan.
Bake for 55 to 60 minutes.
Don't be alarmed if the cake rises and then sinks slightly. Remember, there's no flour or leavening agents in this cake. A little sink is normal.
Remove the cake pan from the baking dish, and allow the cake to cool for one hour at room temperature, then cover it with plastic wrap at refrigerate for at least 2 hours or overnight.