Grease and line two 23cm sandwich tins (that are at least 2" deep), and pre-heat your oven to 180C(160C Fan)/350F/Gas Mark 4
Sift the plain flour, cocoa powder, bicarbonate of soda, baking powder and salt into a bowl and mix together
Add the light brown sugar and mix in, trying to break up any lumps
Melt the butter on a low heat then stir the milk, vegetable oil and the vanilla extract into it
Pour the wet ingredients into the dry and mix it all together well
Split the mixture evenly between the two tins, bake for 30 minutes. Take them out, remove from the tin and leave to cool
To make the chocolate fudge frosting heat the condensed milk with the double cream in a pan on a medium heat until it bubbles. Stir it for about 5 minutes, then take it off the heat and add the butter, the dark chocolate and the vanilla extract. Once they melt, stir the mixture and leave it to cool completely
Put the first sponge layer on a cake stand and spread frosting over it. Add the other sponge layer and cover the whole cake with the frosting
Store leftovers in an airtight container in a cool place and eat within 3 days