600g/1lb 5oz fresh blackberries, hulled
陆 unwaxed lemon, finely grated zest only
1 tbsp fresh lemon juice
fresh mint leaves, to decorate
150驳/5陆辞锄 plain flour
陆 tsp baking powder
150驳/5陆辞锄 caster sugar
2-3 tbsp caster sugar, to sweeten
50g/1戮oz blanched hazelnuts
75g/2陆oz preserving sugar
125驳/4陆辞锄 butter, softened
300ml/10fl oz double cream, well chilled
100ml/3陆fl oz plain natural yoghurt