- Preheat the oven to 170ºC/fan 150ºC/gas mark 3½. Grease and flour a 2.5–3-litre bundt tin.
- Beat the butter and sugar using a wooden spoon or electric mixer until light and fluffy. Add the eggs one at a time, beating well after each addition, and adding a tablespoon of the flour with the fina l egg to help prevent curdling.
- Mix the remaining flour, bicarbonate of soda and salt in a bowl.
- In a separate bowl, combine the yoghurt and vanilla.
- Sift a third of the flour mixture into the egg mixture and stir until just combined, then add half the yoghurt mixture. Repeat until
everything is thoroughly combined. Mix on a low speed for about 15 seconds or beat with a wooden spoon to give it a good mix. Fold in the raspberries, if using.
- Transfer the mixture to the tin, spreading it evenly. Bake for 1 hour or until a skewer inserted into the centre comes out clean. Leave to cool in the tin.
- To make the frosting, beat the butter until creamy, then slowly add the icing sugar and milk. Add enough food colouring to make the frosting your desired shade of pink, then add the raspberry flavouring, if using. Spread the frosting over the whole cake, then decorate with white chocolate stars, as liked.
For something a bit more subtle, it can be frosted in a lighter colour or simply dusted with icing sugar. You can easily adapt the flavour of the sponge by substituting your favourite flavour of yoghurt.
The Clandestine Cake Club Cookbook by Lynn Hill, published by Quercus at £20.