about 200g/7oz blueberries
1 lemon, zest only (use the juice in the icing, see below)
2 tbsp lemon juice
about 150驳/5陆辞锄 raspberries
about 150驳/5陆辞锄 medium-sized strawberries, hulled and sliced
2 tsp baking powder
250g/9oz golden caster sugar
375g/13oz icing sugar
300驳/10陆辞锄 self-raising flour
2 tsp vanilla extract
150驳/5陆辞锄 butter, well softened
125驳/4陆辞锄 butter, well softened
4 free-range eggs
1 tbsp milk
200g/7oz full-fat soured cream