Melt the unsweetened chocolate in a heatproof bowl, using either the microwave or double boiler method. Allow it to cool to room temperature while preparing the rest of the filling.

Beat the softened butter and granulated sugar together in a mixing bowl on high speed for about 3-5 minutes until light and fluffy.

Combine the cooled chocolate and vanilla extract with the butter and sugar mixture, mixing until smooth.

Add eggs one at a time, beating for at least 3 minutes after each addition.

Spoon the chocolate filling into your cooled, pre-baked pie crust and let it chill for at least 4 hours.

Whip the heavy cream with powdered sugar until soft peaks form.

Spread or pipe the whipped cream generously over the chilled pie.

Garnish with chocolate shavings if desired.

Slice the pie with a warm knife and serve it chilled.