Brownie Layer- In a mixing bowl, combine the brownie mix, egg, egg yolk, milk, and melted butter. Generously spray an 8x8 glass baking with nonstick cooking spray and pour in the batter. Use a silicone spatula to level the batter. Bake at 325 degrees for 45-50 minutes.
Snickers Layer - While the brownies are baking, begin to unwrap the Snickers bars. When the brownies have finished baking and are still warm, sprinkle the chopped candy bars over the brownies. Place the baking dish back in the oven for 2 minutes to slightly melt the Snickers.
Caramel Layer - Place the caramel and evaporated milk in a saucepan and melt over low heat. Stir constantly until it is smooth and completely melted. Pour the melted caramel over the Snickers layer.
Ganache Layer - Place the chocolate chips and heavy cream in a microwave-safe bowl. Microwave at 50% power for 60 seconds. Remove and stir. Place the ganache back into the microwave and heat at 50% power for another 30 seconds. Remove and stir. Repeat at 30 second intervals, stirring in between, until the ganache is melted. Pour the ganache over the caramel layer of the brownies.
Allow the brownies to cool completely. Cut the brownies into squares, or strips, if you want them to look like the Choco-Smash Candy Bar.