1. Lightly spray your pan (I used a 7x11 pan, definitely go smaller not larger if you do) or line with with aluminum foil. Melt butter in a very large (trust me on this) pot on low heat.
2. When butter is melted, add in 8 cups of marshmallows (or 10 ounches). Stir until melted.
3. Remove from heat. Stir in remaining 2 cups marshmallows and rice krispie treats.
4. Spread in pan (use a piece of saran wrap lightly sprayed with cooking spray) and press into the pan.
5. For the caramel sauce: In a small saucepan over medium-high heat, whisk together butter, brown sugar, heavy whipping cream, and salt.Bring to a boil (should take about 1 minute), then reduce heat. Simmer for 5 minutes, whisking frequently. Allow to cool slightly then pour over the rice krispie treats. Spread to cover evenly.
6. For the ganache: Heat the heavy cream on low until simmering. Measure your chocolate chips in a seperate bowl. Pour the heated heavy cream over the chocolate chips. Allow to sit for 10 minutes then stir until smooth. Pour over the caramel layer and spread evenly.
7. Allow the ganache to firm up then cut into squares.