2. Melt butter and chocolate in an ovenproof bowl over a saucepan of simmering water stirring occasionally until melted.
3. Add the walnuts, mix through, remove from the heat and set aside.
4. Beat the eggs and sugar together until light and fluffy.
5. Mix the cocoa powder and self raising flour together and add to the chocolate mix.
6. Then fold the egg and sugar mix through the chocolate and flour mix.
7. Gently fold through the chocolate chips and raspberries.
8. Line a square baking tin with parchment paper. Spoon the mixture into the dish and gently distribute over the dish. Place in the preheated oven for 17 to 20 minutes or until a skewer comes out clean.