1. Preheat the oven to 375°F. Place the pie crust in a 9-inch pie dish, crimp the edges, prick the bottom with a fork, line with parchment paper, and fill with pie weights.

2. Bake the crust for 12 minutes, remove the parchment and weights, then bake for 5 to 7 minutes more. Set aside while preparing the filling.

3. Add cranberries, sugar, orange juice, orange zest, and salt to a saucepan. Cook over medium heat for 8 to 10 minutes, stirring often, until the cranberries burst and the mixture thickens.

4. Let the cranberry mixture cool slightly, then blend until smooth. Reserve 1/3 cup of the cranberry mixture for the topping.

5. In a mixing bowl, whisk eggs, heavy cream, milk, vanilla extract, cornstarch, and the blended cranberry mixture until smooth.

6. Reduce the oven temperature to 325°F. Place the par-baked crust on a baking sheet and pour in the cranberry custard filling.

7. Bake for 38 to 45 minutes, until the edges are set and the center has a slight wobble.

8. Warm the reserved cranberry mixture with butter until glossy, then spread it over the cooled pie.

9. Cool the pie to room temperature, then refrigerate for at least 4 hours before slicing.

10. Serve chilled with whipped cream.