When I worked at Luca in London, this was the base for our Eton mess. You can eat it as it is or add lightly whipped cream and crumbled meringues and you have a five-minute pud that tastes the business.
You can use any berries you like: I think raspberries, strawberries and brambles are a winner; red currants also give a nice burst too. Hull and half the strawberries first.
Pleeeeeeeease make sure you use a really good quality balsamic vinegar – a nic