Preheat your oven to 350°F (175°C). In a mixing bowl, combine vegan chocolate cake mix and dry ingredients. Gradually add wet ingredients, mix until smooth. Pour into greased 9-inch springform pan and bake for 25-30 minutes.

Once baked, cool the cake in the pan for about 10 minutes, then transfer to a wire rack to cool completely. Refrigerate for at least an hour.

In a cold mixing bowl, whip vegan heavy cream on medium speed until soft peaks form, about 3-5 minutes. Slowly add melted vegan chocolate and coconut sugar while whipping until fluffy.

Place the cooled cake on a serving plate. Spread a generous layer of chocolate mousse on top, then add more mousse to create a fluffy finish.

Melt the remaining vegan chocolate chips with vegan heavy cream in a heatproof bowl over simmering water until smooth. Pour ganache over the assembled layers, allowing it to drizzle down.

Cover loosely with plastic wrap and refrigerate for at least 4 hours, ideally overnight, to set and meld flavors.

Garnish with fresh berries or cocoa powder, slice with a warm knife, and serve chilled.