Cut the fruit in 1-2 cm pieces, if necessary, put in an oven tray, sprinkle some sugar and flour and mix well until evenly coated

Mix flour and sugar

Cut the butter in cubes and squeeze it into the flour-sugar mixture. It is important to not work the dough. It should just about form a loose ball (without spontaneously crumbling)

Crumble the ball over the fruit. I prefer relatively large crumbles of ~1 cm

Bake for 20 minutes at 225C (fan) or until the crumbles start to brown lightly. Turn off the heat and let cool, leaving the crumble in the heat to let the fruit soften without the crumbles browning much further

Serve either hot with cold custard or vanilla ice cream, or cool with warm custard