Preheat your oven to 375°F (190°C).
In a mixing bowl, combine the flour and salt for the crust. Add the chilled butter and use a pastry cutter or your fingertips to incorporate the butter into the flour until the mixture resembles coarse crumbs.
Gradually add the ice water, one tablespoon at a time, and mix until the dough comes together. Form the dough into a ball, wrap it in plastic wrap, and refrigerate for 30 minutes.
On a floured surface, roll out the chilled dough to fit your 9-inch pie dish. Carefully transfer the dough to the pie dish, pressing it gently into the bottom and sides.
In a saucepan, combine the cranberries and sugar. Cook over medium heat until the cranberries burst and the sugar has dissolved, about 5 minutes. Remove from heat and set aside.
In a separate bowl, whisk together the eggs, heavy cream, vanilla extract, salt, and orange zest (if using). Gradually pour the custard mixture over the cranberries, ensuring they are evenly distributed.
Position the pie dish on a baking sheet and gently transfer it into the oven that has been preheated. Bake for 40-45 minutes or until the custard is set and the crust is golden brown.
Once baked, remove the pie from the oven and let it cool on a wire rack. Before slicing and serving, let it cool completely.