Put crust in a deep dish pie pan, coverwith parchment paper, and fill with pie weights, beans, or marbles.
Bake for 8 minutes. Remove from oven, and put aside weights and parchment. The bottom of the crust should be lightly browned.
Raise oven heat to 400 F.
Melt butter in a medium-sized saucepan on medium heat.
Add apples and sugar and stir frequently for about 8 minutes until apples are soft but not mushy. They will reduce greatly in volume.
Remove from the heat and stir in apple cider liqueur and salt.
Pour apples over pre-baked pie crust.
Whisk together all ingredients and pour over apples.
Bake for 15 minutes.
Reduce heat to 325 F and bake for another 50 minutes. Check on the pie periodically. If the crust is getting too dark, cover with foil or a pie guard.
Cool completely before slicing.
If you aren't sure if your pie pan is deep enough to hold all of the custard, I suggest making all of it and just adding as much as will fit. You can bake any extra custard in ramekins at 350 F for about 30 minutes. It ends up tasting like bread pudding!If you like a higher proportion of custard to apples and you are using a regular pie pan, reduce the amount of apples by half and use the full custard amount.Store the pie at room temperature for up to three days or refrigerated for up to one week.