Prepare the chocolate cake by baking according to package instructions or your favorite homemade recipe. Preheat oven to 350°F (175°C) and mix until smooth. Cool the cake in the pan for 10 minutes, then transfer to a wire rack to cool completely. Cut into 1-inch cubes.

In a large mixing bowl, use an electric mixer to beat the heavy cream on medium speed until soft peaks form, about 3 to 5 minutes. Do not over-whip.

Select a clear trifle dish or glass bowl. Place a layer of chocolate cake cubes at the bottom, spreading evenly.

Drizzle the cake layer with Kirsch if using, then sprinkle cherries over the cake cubes for sweetness.

Spoon a layer of whipped cream over the cherries and cake, spreading evenly. Repeat layering until the dish is full.

Finish with a top layer of whipped cream and sprinkle chocolate shavings and cherries for decoration.

Cover with plastic wrap and refrigerate for at least 2 hours or overnight to allow flavors to meld. Serve chilled.