Preheat your oven to 400°F (200°C).
In a mixing bowl, combine the flour and cold butter. Use a pastry cutter or your hands to mix until it resembles coarse crumbs.
Add ice water gradually, mixing until the dough comes together. Form into a disk, wrap in plastic, and refrigerate for 30 minutes.
Roll out the dough on a floured surface into a large circle. Transfer to a baking sheet.
In a bowl, toss the sliced vegetables with olive oil, salt, and pepper. Arrange them in the center of the dough, leaving a border around the edges.
Fold the edges of the dough over the vegetables, pleating as necessary.
Bake for 45 minutes or until the crust is golden and the vegetables are tender.
Let cool slightly before slicing and serving.