Start by preheating the oven to 350°F, then proceed to butter and flour two 8-inch round cake pans.
Combine sugar, cake flour, cocoa powder, espresso powder, baking powder, baking soda, and salt in a stand mixer bowl. Add eggs, canola oil, buttermilk, and vanilla; mix at medium speed. Gradually add boiling water and beat until well combined. Batter will be thin.
Pour the cake batter evenly into the prepared baking pans. Bake in a preheated oven for 25-30 minutes or until a skewer inserted comes out with just a few crumbs. Afterward, let it cool for a few minutes before removing it from the pan. Transfer it to a cooling rack and allow it to cool completely.
While the cake is baking, prepare the ganache. Heat the cream until it's steaming, then pour it over the chocolate chips in a bowl. Stir until the mixture is completely smooth, and allow it to cool to room temperature. Once it's cooled, use either a stand mixer or a hand beater to whip it until it becomes lighter in color and fluffy.
To craft white chocolate buttercream, begin by whipping the butter until it's light and fluffy. Next, incorporate the cooled white chocolate and vanilla into the mixture. Gradually add powdered sugar in 1/2 cup portions, ensuring you reach the desired stiff yet spreadable texture.
Use a serrated knife to level the cake tops.
Start by placing a cake on your stand or platter, then generously spread the ganache filling on top. Finally, position the second cake on top.
To create a crumb coat, use one-third of the buttercream frosting to thinly cover both the top and sides of the cake. Then, refrigerate for 20 minutes.
After chilling, smoothly spread the remaining frosting on both the top and sides of the cake. Finish by generously sprinkling chocolate shavings over the cake before slicing and serving.
To ensure freshness, refrigerate any leftovers, and remember to remove them from the fridge approximately one hour before serving.