Preheat the oven to 350 degrees Fahrenheit and lightly oil a 6×6 loose bottom cake tin. Add the almond milk, butter, vanilla, orange juice, erythritol and eggs to a food processor and blend well to combine.
Add the ground almonds, cocoa powder, orange zest, ginger, cinnamon, salt and baking soda to the food processor. Blend to combine until you have a smooth and creamy cake batter. You can adjust the quantity of spices as desired, adding more or less to suit your personal tastes.
Add the blackberries and stir them gently through the spiced chocolate cake batter. Spoon the batter into the prepared cake tin. Level the top with a spatula so that it is even. Transfer to the oven to bake for 35 minutes. The cake should be firm on top and cooked through.
Set aside to cool. Once cooled, carefully release the cake from its tin. Slice the cake into 9 even squares and serve or garnish as desired.