Prepare chocolate cake in a 9X13 pan, according to the box. Allow cake to cool for 10 minutes.
While the cake is cooling, prepare the chocolate ganache. Over a double boiler, melt the chocolate and cream and whisk until combined. Remove from heat and whisk in 1 tablespoon of Baileys Liquor.
Using the back of a wooden spoon, poke holes all over the cake. Drizzle ganache over the top of the cake.
In a separate bowl, combine the pudding mix and milk, whisking until combined. Before the pudding sets, pour the pudding over the top the cake and spread with a spatula. Allow cake to set in the fridge for approximately 1 hour.
Prepare Chocolate Mousse according to package Chill mousse in the fridge until cake is set. Top cake with Mousse and chocolate chips/chocolate shavings.