150g/5陆oz fresh blackberries
10g/鈪搊z mixed dried cep (porcini) mushroom powder
20驳/戮辞锄 cornflour
62.5g/2录oz caster sugar
90g/3录oz caster sugar, plus extra to line
200g/7oz good quality white chocolate
butter, at room temperature, to grease
140g/5oz egg whites
60驳/2录辞锄 egg yolks
250ml/9fl oz full-fat milk
300g/10陆oz cep 蝉辞耻蹿蹿濒茅 base (see above)