In a medium/large saucepan, whisk together the sugar, cornstarch, and salt.
⅔ cup sugar (133g), ⅓ cup cornstarch (42g), ¼ teaspoon salt
In another bowl or large measuring cup/jug, combine the egg yolks and milk.
4 egg yolks, 3 cups whole milk (750ml)
Gradually pour the milk/egg mixture into the sugar mixture and cook over medium heat, whisking continuously until the mixture comes to a boil. This will take about 3 - 5 minutes.
Let it boil for about 30 seconds and you see a few bubbles pop on the surface.
Remove from heat and whisk in the butter and vanilla extract.
Add the chocolate and whisk until it is melted and the mixture is well-blended.
10.23 ounces good quality semisweet chocolate, finely chopped (290g or 1 ¾ cups semisweet chocolate chips)
Pour into the baked pie shell and press plastic wrap on the surface, making sure to touch the filling. If you have a smaller pie plate, fill some bowl with the leftover filling and cover them with plastic wrap.
1 baked pie shell (9 inch)
Cool for a few minutes and then refrigerate for at least 3 hours or overnight until it's chilled and firm.
Garnish with whipped cream and grated chocolate, if desired.
Enjoy!
Notes
Tips for Success
If your pie plate is smaller than a 9 inch deep dish pan, you'll probably have some leftover filling. If so, just fill a few small bowls and refrigerate them.
The pie needs to chill for at least 3 hours before serving so that it has time to set.
Store any leftovers in the refrigerator for up to 4-5 days.
Freeze individual slices, wrapped well in plastic wrap, for up to about 2 months. Thaw in the refrigerator overnight before serving.