Bake the pie crust according to package or homemade instructions. Let it cool completely before adding the filling.

Place butter and brown sugar into a saucepan. Cook slowly over medium heat until melted and bubbling smoothly together.

In a bowl, whisk cornstarch with milk until smooth. This helps prevent lumps inside the pie filling later.

Slowly pour the milk mixture into the saucepan. Stir constantly to keep the filling smooth and creamy while cooking.

Continue cooking while stirring often. The filling should become thick enough to coat the back of a spoon.

Whisk egg yolks inside a small bowl. Slowly add some warm filling while whisking to prevent scrambling the eggs.

Pour tempered egg yolks into the saucepan. Stir constantly and cook two more minutes until smooth and glossy.

Remove the saucepan from heat. Stir vanilla extract and salt into the filling for extra rich flavor and balance.

Pour warm butterscotch filling into the cooled pie crust. Spread evenly with a spatula for smooth presentation.

Place pie inside the refrigerator for at least four hours. Chilling helps the filling become firm and slice easily.

Beat heavy cream with powdered sugar until fluffy peaks form. Keep chilled until ready to decorate the pie.

Top chilled pie with whipped cream and butterscotch chips. Slice carefully and serve cold for best flavor and texture.