Place the first cake layer onto a serving plate. Scoop 1 cup of frosting onto the first layer and spread it out. Repeat steps with remaining cake layers. Frost top and sides too.Scoop remaining frosting into a piping bag with a star tip ,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 remaining 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 chocolate bar like you're peeling an apple to create shavings.Place the Reese Peanut Butter Cups in between the frosting dollops.