preheat the oven to 170°fan
put the flour sugar and bicarbonate of soda into a seive and gently seive them in
next add the butter and the eggs the the mix and start mixing all of them together with a whisk
then add the milk and vanilla extract until they are all mixed in
next add chocolate or marshmellows if you want to the mix if you want your cake to be even more delicous
finally get a tin and add parchment paper into it then place the mixture inside and pop it in the oven for 25 minutes