Step 1: Prepare the Cake Base

Cut the ready-made chocolate cake into approximately 1-inch cubes. Place the cake cubes in the bottom of a serving bowl or dish (a trifle bowl works beautifully, but any large bowl will do). Ensure the cake is evenly distributed to create a consistent base layer.

Step 2: Soak the Cake Layer

Slowly and evenly pour the chocolate-flavored milk (or cocoa powder-infused milk/chocolate sauce) over the cake cubes. Add the liquid gradually, allowing the cake to absorb it fully. The goal is to moisten the cake without making it soggy. You may not need to use all of the milk; use just enough to ensure the cake is thoroughly moistened. This step is crucial for adding flavor and creating a soft, melt-in-your-mouth texture.

Step 3: Prepare the Cream Cheese Filling

In a large bowl, combine the softened cream cheese and cold heavy cream. Using an electric mixer (either a stand mixer or a hand mixer), beat the mixture on medium speed until it is smooth and creamy. Be careful not to over-mix, as this can cause the cream cheese to become too thin. Gradually add the sweetened condensed milk and continue mixing until well combined. If desired, add the instant cream powder (this will help to stabilize the filling and make it thicker). Mix until the filling is smooth, thick, and holds its shape. Taste and adjust the sweetness if needed.

Step 4: Layer the Cream Cheese Filling

Carefully spoon the cream cheese filling over the soaked cake layer. Spread the filling evenly to create a smooth, consistent layer. Use an offset spatula or the back of a spoon to ensure the filling reaches all the edges of the bowl.

Step 5: Prepare the Chocolate Ganache

Place the chocolate chips in a heat-safe bowl. In a separate saucepan, heat the heavy cream over medium heat until it is just about to simmer. Remove the cream from the heat and pour it over the chocolate chips. Let the mixture sit for about a minute to allow the chocolate to melt. Gently stir the mixture until the chocolate is completely melted and the ganache is smooth and glossy. If there are any remaining lumps, microwave the mixture in 15-second intervals, stirring after each interval, until completely smooth.

Step 6: Layer the Chocolate Ganache

Pour the warm chocolate ganache over the cream cheese layer. Gently spread the ganache evenly to create a smooth, rich chocolate topping. Tilt the bowl to help the ganache spread to all the edges.

Step 7: Prepare the Chocolate Rice Krispies Topping

If using plain Rice Krispies cereal, melt the 200g of chocolate using a double boiler or microwave. Pour the melted chocolate over the Rice Krispies cereal and mix well until the cereal is evenly coated. Spread the chocolate-coated cereal on a baking sheet lined with parchment paper and let it set for about 15 minutes. Sprinkle cocoa powder over the prepared Rice Krispies (whether using pre-made or homemade). Stir gently to coat the cereal evenly with cocoa powder. This adds a touch of bitterness that complements the sweetness of the other layers.

Step 8: Decorate and Chill

Sprinkle the chocolate-coated Rice Krispies mixture evenly over the chocolate ganache layer. Gently press the topping into the ganache to help it adhere. Cover the cake with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the layers to set and the flavors to meld together.

Step 9: Serve and Enjoy!

Before serving, remove the cake from the refrigerator and let it sit at room temperature for about 15 minutes to soften slightly. This will make it easier to slice and serve. Cut the cake into slices or scoops and serve chilled.