Using a hand or stand mixer, beat the eggs and sugar together until it's three times in volume.
Next, sift the flour and cacao powder together. Using a spatula, fold in the flour mixture by thirds (be extra careful not to overmix).
Place batter into 9-inch round pan. Bake at 350°F for 30 minute. To check the doneness, insert a toothpick into the center of the cake. If it comes out clean, it's ready.
Allow the cake to completely cool and slice it into three or four evenly-sized layers.
To make the soaking cream, whisk the heavy whipping cream and liqueur together. Use a spoon or squirt bottle to saturate each layer with the soaking cream.
Melt the semi-sweet chocolate chips in the microwave, stirring them every 10-15 seconds until silky smooth. Using a stand or hand mixer, whip the melted chocolate, softened butter, and condensed milk together until well-combined.
In a separate bowl, beat the very cold heavy whipping cream until it reaches soft peaks. Fold in the chocolatey butter mixture.
To assemble the cake, place a cake layer on a plate. Spread on a layer of cake cream. Repeat until your run out of cake layers.
Using the remaining cream, decorate the outside of the cake.
Dust sides of the cake with the cacao powder and shaved chocolate. Enjoy!