Blackberry Fool

Video

Preparation

1. For the biscuits, preheat the oven to 200C/180C fan/Gas 6 and line two large baking trays with parchment. Scatter the hazelnuts over a tray and roast for 6–8 minutes until golden-brown, watching closely so they don't burn, then tip onto a board and leave to cool.
2. Beat the butter and sugar in a large bowl until light and creamy. Roughly chop the cooled nuts and add them with the lemon zest, flour and baking powder, stirring (and using your hands if needed) until it forms a ball.
3. Divide the dough into 24 even pieces and roll into balls, spacing them well apart on the trays, then press each to flatten to about 1cm thick.
4. Bake one tray at a time for 12 minutes until very pale golden-brown, then leave to cool on the trays — they'll be soft out of the oven but crisp as they cool. Store in an airtight tin and eat within five days.
5. For the fool, rinse the blackberries, put them in a non-stick saucepan and sprinkle over the caster sugar. Stir in the lemon juice and heat gently for two minutes until they start to soften and release their juices, then remove and reserve 12 berries for decoration.
6. Simmer the rest very gently for 15 minutes, stirring regularly, until very soft, then press through a sieve over a bowl, using the bottom of a ladle to extract as much purée as possible. Leave to cool and discard the seeds — you should have around 325ml of purée.
7. Whip the cream and yogurt in a large bowl until soft peaks form (don't overdo it, as the fruit's acidity will thicken it further). Once the purée is completely cold, adjust the sweetness to taste, pour it into the cream and yogurt, and stir just once or twice until lightly marbled.
8. Spoon into wide glass dishes or one large bowl, keeping it marbled. Scatter with a few tiny mint leaves and the reserved blackberries, sprinkle with a little sugar if you like, and serve with the hazelnut biscuits.