Add flour, powdered sugar, salt, and baking powder to a large food processor and pulse a few times to combine ingredients.
Add butter and pulse until the butter is almost evenly distributed, but not quite.
Add orange juice, and pulse a few more times.
Add water, one tablespoon at a time, pulsing in between each addition, until the dough is almost cohesive. It won't quite form a ball yet.
At this point, empty out food processor onto a piece of parchment paper and fold the dough over onto itself, repeating until the crumbs all become cohesive and you can form a dough ball. If you think it is still too dry, spray it with a little water.
Wrap in plastic wrap and refrigerate while you are making the quiche filling.