Once the cakes are completely cooled, place one cake layer on a serving plate. Spread a layer of the cream filling evenly on top.

Place the second cake layer on top of the cream filling and press gently to secure.

To make the chocolate ganache, heat the heavy cream in a small saucepan over medium heat until it starts to simmer. Remove from heat and pour it over the chocolate chips in a heatproof bowl. Let it sit for a minute, then stir until smooth and glossy.