In a large, heavy saucepan over medium-low heat, bring the milk and butter to a simmer.
⅓ cup milk¹, ¼ cup butter
Reduce heat to low.
Stir in the mini marshmallows until melted.
2 ½ cups mini marshmallows
Add the chocolate and stir in until melted and combined.
10 ounces bittersweet chocolate chips
Remove from heat.
In a separate bowl, beat 1 1/2 cups of the heavy cream to form stiff peaks.
4 cups cold heavy cream
Fold the whipped cream into the chocolate mixture.
Carefully pour the chocolate whipped cream mixture into the pie crust.
9 inch chocolate cookie pie crust2
Press a sheet of plastic wrap to the surface of the pie filling.
Chill for at least 3 hours, or until filling is firm. The pie will continue to set up as it chills.
Just prior to serving, whip the remaining 2 1/2 cups heavy cream with the powdered sugar until it forms stiff peaks.
¼ cup powdered sugar3
Spread the whipped cream over the chilled chocolate filling.
Video
Notes
You can use any milk from skim milk to whole milk in this pie.
I used a pre-made chocolate cookie crust because I haven't been able to get chocolate wafer cookie or chocolate graham crackers. If you prefer, feel free to make a homemade crust for this pie.
The whipped cream is lightly sweetened. Feel free to add more sugar to taste.
I topped the pie with chocolate curls for looks. The pie is also delicious served without chocolate curls.