Preheat the oven to 175oC. Grease and flour a cake tin 24cm in diameter with a removable base and set aside.
Melt the butter in a saucepan. Remove the saucepan from the heat. Add the sugar and the egg and mix well.
Add in the rest of the ingredients and mix until combined. Pour into the greased cake tin and place in the oven for 20 minutes. The cake won’t rise dramatically but you should be left with a set top and gooey middle! Allow to cool while you whip the cream until it becomes stiff.
When you’re ready to serve, spoon generous dollops of whipped cream on top and then decorate with blueberries and raspberries.