Annie Bell's Red Velvet Valentine's Cake

Have ready 2 (or 3 if you have them) 20cm loose-bottom sandwich cake tins. Butter these and line the bases with baking parchment.

Make a heart-shaped template in card or stiff paper by first cutting out a 20cm circle. Fold this in half and trace the outline of half a heart on the half circle. Cut this out with scissors, then unfold it to give a symmetrical heart. Set aside.
Preheat the oven to 190C/170C fan/gas 5. In a food processor, cream the butter and caster sugar together until really light and fluffy, 3-4 minutes.

Add the eggs one at a time, scraping down the sides of the bowl between each addition.Now add the flour in three goes, alternating it with the buttermilk, beginning and ending with flour. Add the salt, vanilla and cocoa powder. Start to add the red food colouring very gradually, a knife tip or drop at a time, until the mixture is a dramatic dusky red.

In a small bowl, mix together the vinegar and bicarbonate of soda, which will fizz, and add to the batter. If using three cake tins, divide the mixture evenly between them (weighing is the best way to ensure even sponges). Bake the cakes for 20-25 minutes or until shrinking from the sides and firm when pressed in the centre.

If using two tins, add a third of the mixture to each one, bake these, and then bake the third sponge while the other two are cooling.

Leave the cakes to cool in the tin for 10 minutes, then turn out on to a rack, remove the paper and leave to cool. Trim the cakes into hearts, using the card template and a sharp knife.

To make the frosting, cream together the butter and icing sugar in a food processor. Transfer the mixture to a bowl and gradually fold in the vanilla extract and cream cheese, adding this a spoonful at a time, until smooth and combined. If you wish, tint the frosting with a little red food colouring.

Spread 2-3 tablespoons of the frosting over one of the cakes using a palette knife, repeat with a second layer (using about a third of the frosting as the filling), then lay the final layer in place and use the remaining frosting to coat the top and sides of the cake.

Generously dust the whole cake with cocoa or use a home-made stencil to dust on heart shapes as in the picture. Cover lightly with clingfilm if wished and chill for 1 hour for the frosting to set. If chilling it any longer than this, remove from the fridge 30 minutes before serving.