Preheat oven to 350 degrees and spray two 9 inch round cake pans with pam baking spray. Set aside
In a large mixing bowl, beat all cake ingredients together until fully combined.
Divide batter between the two baking pans and bake for 25-35 minutes or until a toothpick inserted in the center comes out clean. Cool completely.
Once cooled, remove cakes from cake pan and cut the domes off. Using a cake slicer, slice the two rounds in half. You should end up with a total of 4 rounds.
For the Frosting
In a large bowl cream butter, vanilla, and cocoa. Stir in powered sugar a little at a time. Add heavy cream until you reach your desired consistency. Frosting should be smooth and thick.
For the Chocolate Ganache
In a small saucepan, heat heavy whipping cream until steaming. Place chocolate chips into a heat proof bowl.
Once the heavy whipping cream is heated, pour over the chocolate chips. Allow to sit for 1 minute before whisking until smooth. Pour ganache into the squeeze bottle.
Putting It all together
Place the first cake layer onto platter. Evenly spread about 1 cup of frosting onto it. Repeat with remaining layers.
Frost sides and top of cake as well. Scoop remaining frosting into a piping bag and set aside
Using the squeeze bottle, to create a drizzle effect around the top of the cake. Squeeze some ganache over the side allow the chocolate ganache to drip down
Pour ganache onto the center of the top of the cake and smooth evenly to coat the top. Allow to sit for 10 minutes to allow ganache to harden
Pipe dollops of frosting onto the top cake
Take the potato peeler and run it along the edge of the Hershey Bar like you're peeling an apple to create chocolate shavings.