In a food processor, combine the flour, sugar, and salt; pulse briefly. Add cubed butter and pulse until resembling pea-sized pieces.

Gradually pour in ice water while pulsing until dough starts to come together. Form into 2 disks, wrap in plastic, and refrigerate one disk for at least an hour.

Preheat oven to 450°F (232°C).

On a floured surface, roll out pastry into an 11-inch circle and place on a parchment-lined baking sheet.

Peel, core, and cut apples into chunks. Toss with orange zest and layer onto dough, leaving a 1.5-inch border.

In a bowl, combine topping ingredients and mix with remaining butter until crumbly; sprinkle over apples.

Pleat the edges of the pastry over the filling to create a rustic border.

Bake for 20-25 minutes or until golden brown and apples are tender. Cool for 5 minutes before transferring to a wire rack.