Preheat the oven to 325°F (163℃).
In a small microwave-safe bowl, microwave the chocolate for about 30 seconds, then add the butter. Continue melting in the microwave in 30-second intervals, stirring after each interval, until completely melted and smooth. Set aside.
Line the bottom of the pie crust with parchment paper and add dried beans or ceramic pie weights on top. The beans keep the bottom of the crust from rising.
Bake for 5-6 minutes in the preheated oven, remove from the oven, and let it cool. You want the pie crust to cook but not brown.
In a large mixing bowl, whisk the granulated sugar, cornstarch, and cocoa powder.
Then add eggs, evaporated milk, and vanilla extract.
Finally, add the melted chocolate and butter.
Pour the filling into the pie crust and bake at 325°F (163℃) for 35-40 minutes or until the top is nicely browned or when a skewer inserted in the middle of the pie comes out clean (see notes).
Allow to cool completely before slicing and serving. Serve with a dollop of this homemade whipped cream and strawberries, if desired.