Step #1
Line a 19 x 28cm (7½x11 inches) oblong tray with baking parchment. Mix all the ingredients under cake and follow the instructions on the back of the pack.
Step #2
Pour the cake batter into the tin.
Step #3
Rub the butter into the 75g of cake mix. (Don’t worry if this starts to stick together). Mix in the porridge oats breaking any lumps of chocolate mixture.
Step #4
Scatter half of the oat topping on top of the cake batter. Sprinkle over the raspberries.
Step #5
Scatter the remaining oat topping and press down lightly.
Step #6
Bake in a preheated oven 190°C (375°F) gas mark 5 for 45-50 minutes until firm to the touch. Leave in the tin to cool for 10 minutes before turning out.
