1.Preheat oven to 200°C (180°C fan-forced). Place apple, pear, berries and sugar in a 6-cup ovenproof dish and toss to combine. Bake for 15 minutes.
2.Meanwhile, make topping: Place flour, caster sugar and baking powder in a bowl. Rub in butter with fingertips until mixture resembles breadcrumbs. Add buttermilk and mix to combine.
3.Dollop spoonfuls of topping roughly over fruit and sprinkle with demerara sugar. Bake for 40-45 minutes, until topping is risen and golden. Set aside for 15 minutes before serving with custard or ice-cream.
Tip: Leave a little fruit uncovered – it looks more attractive if the filling is visible among the golden topping.