Blackberry, marshmallow and mascarpone trifles

Method

1. Heat 900g of the blackberries in a pan with a splash of water and the sugar for 10 minutes until the berries start to break down. Whizz until smooth in a food processor or liquidiser, then pass through a fine sieve into a jug.
2. Divide the remaining blackberries, marshmallows and sponge fingers among 8 glasses. Stir the crème de mûre into the sieved blackberries, then pour 100ml of the liquid back into the pan to heat. Squeeze the 6 gelatine leaves dry, then add to the pan. Remove from the heat, stir until dissolved, then pour back into the jug of liquid. Stir, then divide among the glasses. Chill until set.
3. For the custard, bring the milk to a boil in a pan, then remove from the heat. Meanwhile, whisk the yolks and sugar together. Add a little of the hot milk to the yolks, then pour the yolk mixture into the saucepan and stir over a low heat for about 10 minutes until the custard coats the back of a spoon. Squeeze the gelatine leaves dry, then add to the custard and stir. Pass through a fine sieve, cool slightly, then pour into the glasses on top of the set jelly. Chill until firm.
4. Beat the mascarpone with the cream and icing sugar until stiff, then spread over the top of the custard and smooth with a spatula. Top with chopped blackberries, if you like. Chill until ready to serve.