Preheat the oven to 425°F (220°C).
Prepare the pie crust in a 9-inch pie dish.
Peel, core, and slice the apples. Toss them with lemon juice, cinnamon, and a pinch of salt.
In a saucepan, melt the butter over medium heat, then add brown sugar and heavy cream. Stir until combined and smooth.
Remove the saucepan from heat and let it cool for a few minutes. Then whisk in the eggs and vanilla extract.
Layer the sliced apples into the pie crust, then pour the toffee mixture evenly over the apples.
Bake in the preheated oven for 30-35 minutes until the crust is golden and the filling is bubbly.
Let the pie cool slightly before serving with vanilla custard or drizzled toffee.