• Place a large metal or glass mixing bowl and beaters in the freezer to chill. This will be used to whip the heavy cream.

To prepare the crust:

• Lightly spray a 9-inch pie place with vegetable cooking spray. Set aside.
• Break the Oreo cookies into chunks and place in the bowl of a food processor. Pulse about 15 times to coarsely chop the cookies. Process another 15-20 seconds or until you have fine crumbs. Add the melted butter and pulse until combined. Make sure the butter is evenly distributed into the mixture.
• Press the cookie crumb mixture into the bottom and up the sides of the pie plate and freeze for 15 minutes. While the crust is chilling, preheat the oven to 325°F.
• Bake for 16 to 19 minutes or until the chocolate is fragrant and the crust is set. If the crust starts to slump or slide down into pie pan, gently press it back into place using the back of a spoon. Set aside on a rack to cool completely before filling.

To prepare the filling:

• Blend the hot water, espresso powder, cocoa, vanilla and salt in a small bowl. Set aside.
• In a medium bowl microwave the chopped chocolate on 50% powder for 1 minute. Stir and repeat with 30-second intervals as needed until most of the chocolate is melted. Continue stirring occasionally until all chocolate is melted and smooth. Set aside to cool for about 5 minutes.
• Pour 1 ½ cups heavy whipping cream into a large chilled mixing bowl. Beat on medium speed until soft foamy peaks start to form. Add the sugar and beat on high until soft peaks form. Using a spatula gently fold in the water and cocoa mixture until blended.
• Transfer about ⅓ of the whipped cream mixture into the melted cooled chocolate. Gently fold together until blended.
• Next transfer all the melted chocolate mixture to the bowl with the cocoa whipped cream. Fold gently using a spatula until no streaks of whipped cream remain. Take care not to deflate the mixture.
• Spread the filling into the cooled, prepared cookie crust. Refrigerate until set, about 2 to 4 hours.

To prepare the whipped cream topping:

• In a large cold mixing bowl using an electric mixer, beat the cream on medium speed until soft peaks form. Add the powdered sugar and vanilla and beat on high until firm and silky (not dry) peaks form. Dollop the whipped cream on top of the pie and swirl decoratively. Garnish with cookie crumbs, grated chocolate or chocolate curls if desired.