Meanwhile, prepare apple cider reduction. Pour apple cider in a saucepan and bring to a boil over medium heat. Cook until it reduces to about ½ cup and coats the back of a spoon, about 30 minutes. Remove from heat and let cool to room temperature.

Preheat oven to 375 degrees F.

Line pie dough with parchment paper and fill with pie weights. Bake 15 minutes. Remove from oven and remove parchment paper and weights. Bake 5-7 minutes more, just until the surface looks dry and set and is barely blond. Remove from the oven and let cool.

Reduce oven temperature to 350 degrees F. Preheat a baking sheet on the bottom rack for at least 10 minutes.

Prepare apples. Melt butter in a large skillet over medium heat. Add apples, brown sugar, lemon juice, cinnamon, and salt. Cook until just tender, 6-8 minutes. Spread on a plate to cool and drain off any liquid.

Make custard. Whisk eggs and yolk with sugar until smooth. Add heavy cream, milk, cider reduction, vanilla, cinnamon, salt, and nutmeg.

Arrange the cooled apples in an even layer in the crust. Pour the custard over the apples, filling to just below the rim. Place pie on preheated baking sheet and bake for 40-50 minutes or until the edges are set and the center still has a slight jiggle.

Remove from oven and cool on a rack to room temperature. Transfer to the refrigerator and chill for at least 3 hours, ideally overnight.

Make the cider whipped cream. Beat cold heavy cream to soft peaks. Add the powdered sugar and cider reduction and continue to whip until medium peaks. Slice and serve the pie with apple cider whipped cream.