One 20 cm (8 inch) round cake (we used butter cake, but you could use chocolate, or coconut cake)
50 g (l /4 oz) unsalted butter
120 g (4 oz) icing sugar, sifted
3 teaspoons liqueur (Cointreau, Grand Marnier etc) a few drops of red food coloring
500 g (1 lb) soft icing (ready-made ) icing sugar
1 - Draw round the base of the cake tin and cut out a 20 cm (8 inch) circle from a piece of paper. Fold the circle in half and draw on half a heart shape using the fold as the middle of the heart and the outside edge as the edge of the heart. Cut along this line and unfold the paper to make a heart-shaped template.
2 - Cut the domed top off the cake to give a flat surface. Turn the cake upside down and use the template to cut into a heart with a serrated knife. The cake should cut easily and leave a clean edge.
3 - To make the pink buttercream, beat the butter until soft, add the sifted sugar and continue beating until light and fluffy. Add the liqueur and colouring and beat well.
4 - Cut the cake in half horizontally. Spread the bottom layer with a third of the butter cream and sandwich the halves together.
Spread the remaining buttercream over the cake in a thin layer, to help the next layer of icing stick. Place the cake on a serving plate or board.
5- Knead the icing until smooth on a surface dusted with icing sugar. Add a couple of drops of food colouring and knead into the icing until it is pale pink (you may need to add more icing sugar as you go along). Pull off a piece the size of a golf ball and add another few drops of food colouring to make it darker. Continue doing this until you have three or four different shades of pink icing set aside. Roll out the remaining icing into a circle large enough to cover the top and side of the cake. Carefully drape this over the cake, easing it into the corners and around the edges until it fits snugly all over. As long as you don't over-roll your icing you should not have any folds or pleats—if you do then just smooth them in. Trim away any excess and set it aside.
6 - Roll out the balls of colored icing and stamp out heart shapes using varying sized cutters. If you want any of the hearts to be red, paint them with the food coloring and leave to dry. Mix 1 tablespoon of icing sugar with a little water to make a runny paste and use a tiny dab of this to stick each heart onto the cake.
Fold the paper circle in half, draw half a heart on one side and cut out.
Put the paper template over the cake and cut with a serrated knife.
Ease the icing into the corners and around the edges until it fits snugly.
Roll out the balls of coloured icing and cut out heart shapes of different sizes.
Ahead of time: This cake will keep for up to 3 days in an airtight container after icing.