Nigel Slater freeform trifle with raspberries and custard recipe on Saturday Kitchen

Nigel Slater served up a delicious freeform trifle with raspberries and custard on Saturday Kitchen.

The ingredients are: 500g mixed berries (blueberries, raspberries, blackberries), 3 tbsp sugar, or more to taste, splash water, 500g ready-made plain sponge cake, 250ml ready-made custard and icing sugar, to serve (optional).