Pear & Berry Crumble

You can use any ripe sweet fruit you like for this, really — peaches, apples, apricots, nectarines, pineapples... This is best served warm, when it has cooled down a bit, with a jug of warm custard or just a blob of thick or clotted cream on the side, and a dusting of icing sugar. Sometimes I like the crumble topping to be soft soft, and then I use 60 g (2