1. Preheat the oven in 350ºF (180ºC).
2. Butter a 9x9 inch (23x23 cm) glass or ceramic dish or 6 individual ramekins.

For the fruit layer:

1. Peel and core the apples. Cut them into medium wedges or dice.
2. Mix the apple pieces with the orange juice, zest, sugar, cornstarch, cinnamon, and vanilla in a bowl.
3. Transfer to the prepared baking dish.
4. Alternatively, cook the above mixture in a saucepan over low/medium heat until apples start to soften and release some of their juice, about 5 minutes. Don't let them soften too much.

For the crumble topping:

1. In a food processor: put the flour and sugar in the bowl with the steel blade. Pulse once or twice.
2. Add cold butter and pulse until the butter is the size of peas.
3. In a bowl: put the flour and sugar in a large bowl, add the cold butter pieces and with your hands or a pastry blender, mix until the butter is the size of peas.

To assemble:

1. Put the apple mixture in the baking dish and top it with the blackberries.
2. Sprinkle the crumble mixture over the fruit. It will be very irregular and that is fine.
3. Bake for 35 to 40 minutes or until golden brown and berry juices are bubbling.
4. Cool until warm and serve with whipped cream or vanilla ice cream.
5. Or eat it plain, at room temperature.