Preheat oven to 350 degrees F.
Blind bake the pie shell. Set aside to cool.
In a small saucepan
the butter over medium heat. Add the chopped chocolate and remove from the heat. Mix until the chocolate is melted.
in the sugar, eggs, liqueur
, flour, salt, and vanilla. Pour the filling into the pie shell. Bake for 28 to 30 minutes, or until the chocolate moves slightly. Let cool completely on a rack at room temperature.
Serve the pie by itself, topped with whipped cream.
To turn it into an amazing milkshake:
Chill the pie
until firm. Cut into 8 slices. For each shake, in a blender, add 1 slice of the pie, 1/4 cup whole milk, 5 ounces ice cream, and 1 full-size Peppermint Patty
. Turn on the blender
and let it rip. Voila! Awesome milkshake. Serve topped with whipped cream and a mini Peppermint Patty.