Preheat the oven to 180 degrees and prepare your cake tin by greasing the sides and lining the bottom.
Mix the flour, baking powder, bicarbonate of soda, cocoa powder and sugar together in a bowl
In a separate jug mix the milk, oil, golden syrup and vanilla extract
Pour the wet ingredients into the dry and whisk together until there are no dry bits
Add in 15g of the chocolate chunks and mix in
Pour the mixture into the cake tin
Lightly drop the remaining chocolate chunks on to the top of the cake
Put the cake into the oven and bake for 40 to 50 minutes. Check the cake after 35 minutes with a skewer. Continue cooking until the skewer comes out clean
Once the cake has baked leave it to cool for 15 minutes before taking it out of the tin
Leave the cake to cool completely and enjoy!