Blackberry Fool

For the biscuits, preheat the oven to 200C/180C (fan)/Gas 6 and line two large baking trays with baking parchment. Scatter the nuts over a baking tray and roast in the oven for 6-8 minutes, or until golden-brown. Watch them carefully so that they don’t have a chance to burn. Remove from the oven, tip onto a board and leave to cool. Put the butter and sugar in a large bowl and beat with a wooden spoon until light and creamy. Roughly chop the cooled nuts and add to the creamed butter and sugar, along with the lemon zest, flour and baking powder. Stir well until the mixture comes together and fo