First make the chocolate ganache. Pour the chocolate chips into a large bowl. Heat the heavy cream in a small pot until it becomes hot and just begins to have bubbles coming up along the sides. Pour the hot cream over the chocolate and stir until all of the chocolate is melted and they are completely combined. Allow it to cool for 2 hours, then whisk it with an electric mixer for a minute or two to help it gain some air and fluffiness.

While it is cooling, make the caramel. In a small thick-bottomed saucepan mix together the water and the granulated sugar until well blended. Bring to a boil over medium-low heat and continue boiling until the mixture turns a light caramel color, only stirring once every four minutes. This took me about eight minutes, but the speed will depend upon the heat of your stovetop. Remove the pan from the heat and quickly stir in the heavy cream, butter, and brown sugar until incorporated. Be careful as the mixture will spit and hiss a bit. If the sugar begins to clump up when you're stirring do not fret, just stir as best as you can for about 30 seconds and then put the pot back on the heat and bring it back to a boil again over medium-low heat. Once it is boiling again stir until the sugar chunk dissolves and the mixture is smooth. Once it smoothes out, reduce heat to low and stir it every two minutes, allowing the mixture to simmer for at least 15 minutes or until it has thickened significantly. Remove from the stovetop and stir in the salt. Allow to cool completely to room temperature.

Line an 8-inch cake pan with plastic wrap, making sure there is excess wrap that is hanging over the sides. Evenly spread the nuts and 1/4 cup of chocolate chips over the bottom of the pan, keeping the nuts at the very bottom flush with the bottom surface so that they are more visible when the cake is eventually flipped over. Then spread the caramel gently over the top of the nuts. Once there is an even layer of caramel, evenly spread the chocolate ganache over the caramel layer. Place the pan in the refrigerator uncovered, for 4 hours or overnight.

Remove the pan from the refrigerator and flip the pan over onto the serving surface. The cake should come out when you pull up on the pan, and the cake should still have the plastic wrap stuck to it. Gently peel the plastic wrap off of the cake and allow to sit at room temperature for 20 minutes before serving.