Pre heat the oven to 160C Fan/180C/350F/Gas Mark 4 and grease and line a 2lb loaf tin
Make the pink sponge first. Mix the butter and sugar together until fluffy, ideally with an electric mixer, or you can mix in a bowl with a wooden or silicone spoon
Add eggs and vanilla extract and whisk in
Whisk in the self raising flour, and add enough pink food colouring to get a strong shade
Pour the mixture into the loaf tin and bake for around 50 minutes or until a skewer inserted in the centre comes out clean
Leave it to cool completely, then cut off the ends of the sponge, then score marks along it the same thickness as your heart shaped cutter
Cut the sponge into slices following the scored lines and then use your heart shaped cutter to cut out hearts from each piece
Make the chocolate sponge. Mix the butter and sugar together until fluffy, ideally with an electric mixer, or you can mix in a bowl with a wooden or silicone spoon
Add the eggs and milk, and whisk in
Whisk in the self raising flour, baking powder and the cocoa powder
Put some of the mixture into the bottom of the tin, and set the heart shaped pink cake into it neatly in a row
Spoon the remaining mixture around and on top of the pink sponge hearts, or you can pipe the cake batter in using a piping bag
Bake for around 50 minutes or until a skewer inserted in the centre comes out clean, allow to cool fully
To make the buttercream mix together the icing sugar, vanilla extract, milk and butter. Then add the melted dark chocolate and mix until smooth. If the buttercream is too stiff then you can add a little more milk
Spread or pipe the buttercream over the sponge and sprinkle on some heart sprinkles too if you like
Slice to reveal the hidden heart design! Store leftovers in an airtight container in a cool place for up to 3 days