Grease and line a 23cm square cake tin. Preheat the oven to 200℃ /180℃ fan/gas mark 6.
Break the chocolate into pieces and place in a bowl over a pan of hot water with the butter. Heat gently, stirring until melted and combined.
Remove the bowl from the heat. add the sugar and mix well. Add the eggs one at a time and beat in. (If the mixture is very hot allow to cool slightly before adding the eggs.)
Sift the flour and cocoa powder into the bowl and mix to combine.
Pour into the prepared tin and scatter the blackberries evenly over the surface.
Bake for about 30 minutes until just cooked. Cool in the tin. Cut into squares to serve
Notes
Nutrition information is calculated usingan online nutrition database - is approximate and is meant as a guideline only. Freeze: For up to 3 months