For the Cookie Crust:
For the Flourless Chocolate Cake:
For the Pudding:
For the Whipped Cream:
So, thie recipe seems like a lot and there are definitely a several steps but each is easy so fret not...
First, make the crust. Preheat the oven to 300 degrees Fahrenheit. Lightly spray a 9-inch springform pan with nonstick cooking spray. Line pan with parchment paper and lightly spray parchment and sides of pan. Place cookies in the bowl of a food processor; process to very fine crumbs. Add the melted butter. You should have about 3 1/2 cups. Pour crumb mixture into prepared springform pan and press evenly with the bottom of a measuring cup into bottom and up sides, leaving about 1/2 inch between the top of the crust and top of the pan. Transfer to freezer until crust is set, about 10 minutes. Transfer crust to oven and bake until dry to the touch, about 10 minutes. Transfer pan to a wire rack and let cool.
Next, make the Flourless Chocolate Cake: Increase oven temperature to 350 degrees. Place butter and chocolate in a microwave proof bowl. Blitz on high for 2 minutes, stirring every 30-seconds until almost melted (residual heat as you stir will melt any small chunks). Set aside. In a small bowl, whisk together espresso powder, coffee, salt, and vanilla; set aside. In the bowl of an electric mixer fitted with the whisk attachment, beat egg yolks with 1/2 cup sugar until light and almost doubled in volume, about 5 minutes. Add melted chocolate mixture and beat until just combined. Scrape down sides and bottom of the bowl and mix on low speed for 5 seconds. Add coffee mixture and beat until just combined. Scrape down the sides and bottom of the bowl and mix on low for 5 seconds.
In the clean bowl of an electric mixer fitted with the whisk attachment, beat egg whites until foamy. Gradually increase speed to high and slowly add remaining 1/2 cup sugar, beating until soft peaks form. Transfer 1 cup egg white mixture to chocolate mixture and, using a rubber spatula, gently fold to combine, about 30 seconds. Add remaining egg whites and continue gently folding until they are almost completely combined; do not overmix. Pour cake batter into the cooled cookie crust, being careful not to over fill...you may actually have some batter leftover. Transfer to the middle rack of the oven. Bake until the cake is set but still jiggles slightly, 38 to 42 minutes. It may not appear completely cooked. Transfer to a wire rack to cool completely. Cake will deflate in the center as it cools. Tightly wrap cooled cake with plastic wrap and refrigerate at least 3 hours and up to overnight.
Meanwhile, make the chocolate pudding. Clearly, we used the instant stuff, but should you want to remain a purist, the lovely Bake or Break made this cake and her recipe is here. If, however, you want to elimnate a step, make two packets of good instant chocolate pudding according to the package instructions. Then, press a piece of plastic wrap directly on the surface of pudding to prevent a skin from forming. Transfer to refrigerator until chilled, at least 3 hours.
After 3 hours, stir pudding to loosen and pour on top of cake, again making sure to stay within the cookie crust border and not over fill. Using an offset spatula, spread pudding to form an even layer on top of the cake. Transfer to refrigerator for 30 minutes.
Prepare the Whipped Cream Topping: In the chilled bowl of an electric mixer fitted with a chilled whisk attachment, beat cream until soft peaks form, about 1 minute. Sprinkle sugar over cream and continue whisking until stiff peaks form. Spread whipped cream over chilled pudding layer, working all the way out to the sides.
Unmold cake and serve immediately. The cake can also be kept, covered, refrigerated, for up to 2 days.