Step 4: Make the Chocolate Ganache Swirls Melt the semi-sweet chocolate chips with the heavy cream in a microwave-safe bowl until smooth. Transfer the melted ganache to a zip-lock bag and snip off a corner to create a piping bag. Drizzle the ganache over the marshmallow whipped cream in a decorative pattern. Use a toothpick or skewer to swirl the ganache into the whipped cream, creating a marbled effect.

Step 5: Chill and Serve Once the cake is fully assembled, refrigerate it for at least 30 minutes to allow the layers to set properly. When ready to serve, cut the cake into squares, making sure each piece gets a bit of the cake, ganache, and marshmallow topping. The result is a rich, chocolatey dessert that’s sure to satisfy even the most serious chocolate cravings.

Notes
Substitute with milk chocolate: If you prefer a sweeter chocolate experience, you can substitute the semi-sweet chocolate chips with milk chocolate chips. This will create a sweeter, creamier ganache filling and topping.
Try different toppings: Feel free to add extra toppings, such as crushed graham crackers for a slight crunch or even a drizzle of caramel sauce for an added layer of flavor.
Customize with mix-ins: For added texture, you can stir in chopped nuts, like walnuts or pecans, into the ganache filling or sprinkle them on top with the chocolate ganache swirls.