Preheat oven to 325 degrees.
Grease a 9 inch pie plate very well with butter or spray with baking spray with flour.
In a small pan, melt butter and unsweetened chocolate. Set aside to cool.
Using a stand mixer with a paddle attachment or hand mixer, beat the eggs.
Add sugar and beat until light and creamy.
Pour in vanilla and beat.
Add cooled chocolate mixture and beat until incorporated.
Add flour, salt and milk and beat until smooth.
Fold in semi-sweet chocolate chips.
Pour into prepared pie plate. Spread evenly. Sprinkle granulated sugar over the top.
Bake for 40-45 minutes or until a toothpick comes out mostly clean.
Let cool. If desired add a scoop of vanilla ice cream and drizzle chocolate sauce over the top.
Serve warm, room temperature or cold. Enjoy!