The basic crumble mix is half sugar and fat to flour. e.g. for 4 people, 6oz plain flour, 3 oz butter or marg, and 3 oz sugar. I sometimes add ground almonds, or use demerera sugar, this makes it more crunchy. Add blackberries, raspberries, strawberries or pears, to the apples for a change. I never pre-cook the fruit. The crumble would take about 35-40 minutes to cook at 170c, depending on your oven.
Oh and the other week I did it with plums, just quartered them (removing the stone of course!), sprinkled with cinamon. They were very tastey, but there was a lot more fluid than I anticipated.
Snoopysue
Logic merely enables one to be wrong with authority.