Heat oven to 180C/fan 160C/gas 4. Grease and line a 20cm cake tin.
Place the butter, caster sugar, brown sugar, chocolate and golden syrup in the pan and melt gently on a low heat until it is smooth and lump-free.
Remove the pan from the heat.
Break the eggs into the bowl and whisk with the fork until light and frothy. 5 Add the eggs, vanilla extract or essence, flour, baking powder and cocoa powder to the chocolate mixture and mix thoroughly.
Put the mixture into the greased and lined cake tin and place on the middle shelf of the oven. Bake for 25-30 mins.
Remove and allow to cool for 20-30 mins before cutting into wedges and serving.
Serve with cream or ice cream and plenty of fresh fruit.