Preheat the oven 170°C/310°F/Gas mark 3½. Grease and line a 15 cm (6 in) cake tin (pan).
In a large mixing bowl, cream the butter and sugar together until pale and smooth, about 2–3 minutes using an electric mixer.
In another bowl, beat the eggs with the vanilla, then pour gently into the butter and sugar mixture, a little at a time, and continue to mix for a few minutes after each addition.
Sift the flour into another bowl. Add the flour and milk in alternate batches to the butter and sugar mixture, beating well after each addition until all has been incorporated.
Tip the batter into the prepared tin and bake for around 30 minutes, or until slightly raised and golden brown.
Pierce the centre of the cake with a skewer and if it comes out clean the cake is ready. Leave in the tin to set for 10 minutes before turning out onto a wire rack to go cold.
Meanwhile, to make the decoration, beat the butter in a bowl to soften it. Add the icing sugar and a dash of milk, if needed, and stir to combine.
Crumble the cake into a large bowl. Add some of the buttercream and mix together using your hands until it becomes a dough-like texture and you can roll a ball of the mixture.
Roll balls of mixture to the size of a golf ball and place on a flat surface.
Break a few chunks of chocolate into a small bowl and set over a pan of gently simmering water until melted.
Dip 1 cm (3/8 in) of each lollipop stick in to the melted chocolate and stick one into each cake ball. Freeze until frozen.
Melt the rest of the chocolate as before. If you are using white chocolate, colour it with food colour, if you like. Dip each cake ball in the chocolate so that each is fully coated. Stand in foam or polystyrene until set.
Recipe taken from Britain's Best Bakery, available from New Holland Publishers, RRP: £24.99.