In a large bowl, whisk together the flour and salt. Add the cold, cubed butter. Using a pastry blender or your fingers, cut the butter into the flour until the mixture resembles coarse crumbs. Slowly add the ice water, one tablespoon at a time, mixing until the dough just comes together. Be careful not to overmix. The dough should be slightly shaggy.

Form the dough into a disc, wrap it in plastic wrap, and refrigerate for at least 30 minutes. This chilling time is crucial because it allows the gluten to relax, resulting in a tender crust.

While the dough is chilling, make the cranberry orange filling. In a medium saucepan, combine the cranberries, sugar, orange juice, and orange zest.

Cook the cranberry mixture over medium heat, stirring occasionally, until the cranberries begin to burst and the mixture thickens slightly, about 8-10 minutes.

In a small bowl, whisk together the cornstarch and water to create a slurry. Pour the cornstarch slurry into the cranberry mixture and stir continuously until the filling thickens. This usually takes about 1-2 minutes. Remove from heat and let it cool slightly.

Preheat your oven to 375°F (190°C). On a lightly floured surface, roll out the chilled dough into a 12-inch circle.

Carefully transfer the dough to a 9-inch tart pan with a removable bottom. Press the dough into the bottom and up the sides of the pan. Trim any excess dough from the edges.

Pour the slightly cooled cranberry orange filling into the tart shell, spreading it evenly.

Bake the Cranberry Orange Tart for 25-30 minutes, or until the crust is golden brown and the filling is bubbly.

Let the tart cool completely on a wire rack before serving. This allows the filling to set properly. Once cooled, remove the tart from the pan by gently lifting the bottom of the removable pan.