Preheat your oven to 180c and line a brownie tin with grease proof paper.
Gently melt the butter, cacao powder and dark chocolate together until smooth and silky.
Beat in the eggs one at a time, then wisk in the maple syrup.
Fold through the dry ingredients to create a smooth batter, then pour into your lined tin. Swirl the blackberries and chocolate chips through the mixture and pop these into the oven to bake for around 18 minutes.
Once your brownies are cooked through, transfer onto a cooling wrack whilst you prepare the frosting.
Gently melt the chocolate and whisk this into the maple syryp and cacao powder. Gradually drizzle in a little non-dairy milk whilst whisking until you reach a smooth, responably thick consistency.
Spread the frosting over your cooled brownies and pop into the fridge for 10 minutes before slicing into portions.