Preheat the oven to 375°F (190°C).
In a large mixing bowl, combine the sliced apples, toffee bits, lemon juice, cinnamon, and a pinch of salt.
Roll out the pie crust and fit it into a 9-inch pie pan.
Pour the apple and toffee mixture into the pie crust.
Bake the pie for 40-45 minutes, or until the apples are soft.
While the pie is baking, prepare the vanilla custard.
In a saucepan, whisk together heavy cream, sugar, and cornstarch until combined.
Add the egg yolks one at a time, whisking constantly.
Heat the saucepan over medium heat, stirring constantly until thickened.
Stir in vanilla extract and let the custard cool slightly.
Once baked, allow the pie to rest for 10 minutes before serving with vanilla custard.