Make the crust: Preheat the oven to 350°F (180°C). Grease a 9-inch (23 cm) springform pan with nonstick spray and line the sides with a strip of parchment paper, trimming it flush with the top of the pan.
In a large bowl, stir together the cookie crumbs and melted butter until the crumbs are evenly moistened. Transfer the crumbs to the prepared pan and use the bottom of a measuring cup to press them into an even layer over the bottom of the pan. Set the pan aside while you make the brownie layer.
Make the brownie layer: In a large glass bowl, combine the chocolate and butter and microwave on high power, 30 seconds or until melted and smooth.
In a separate large bowl, whisk together the granulated sugar, brown sugar, salt, vanilla, and eggs until lightened in color and foamy, about 1 minute. Pour in the melted chocolate mixture and whisk until smooth. Add the flour and stir until just combined.
Pour the batter over the crust in the pan and smooth out the top with a rubber spatula. Bake until a toothpick inserted halfway between the center and the edge comes out clean, about 40 minutes.
Meanwhile, make the pudding layer: In a medium saucepan, whisk together the granulated sugar, cocoa powder, flour, and salt until combined. Add the egg yolks and a splash of the milk and stir until it the mixture forms a thick, smooth paste. Add the remaining milk and whisk until smooth. Set the pan over medium heat and cook, stirring continuously, until the mixture starts to bubble and thicken, 8-10 minutes. Remove the pan from the heat, and add the butter and vanilla and stir until the butter has melted and the mixture is smooth and well combined.
When the brownie layer is ready, transfer the pan to a wire rack, pour the warm pudding over the brownie layer, and smooth out the top with a rubber spatula. Let cool to room temperature, about 1 hour. Cover and refrigerate for at least 4 hours, or up to 1 day.
When ready to serve, whisk the chilled cream in a medium bowl until it forms stiff peaks.
Remove the pie from the refrigerator. Remove the outer ring of the springform pan, then peel away and discard the strip of parchment paper and set the pie on a serving plate. Spread the whipped cream over the top of the pie, and dust with additional cocoa powder. Serve the pie chilled.
Need easy dinner ideas?
These meals will make your weeknights way simpler. (And tastier!)