Crush the cookies into fine crumbs using a food processor or by placing them in a ziplock bag and crushing with a rolling pin.
In a mixing bowl, combine the cookie crumbs, softened butter, and chopped walnuts. Mix until the texture resembles wet sand.
Press this mixture evenly into the base of a springform pan or a lined baking dish to create a firm crust. Refrigerate while you prepare the cream layer.
Step 2: Whip the Cream Layer
In a large bowl, whip the cream until soft peaks form.
Add the condensed milk and sifted cocoa powder into the whipped cream. Gently fold until smooth and well combined.
Spread the cream mixture evenly over the cookie base. Smooth the top with a spatula for an even finish.
Step 3: Make the Chocolate Glaze
Melt the dark chocolate with the butter in a heatproof bowl over simmering water (double boiler method) or in the microwave in 20-second intervals. Stir until smooth and glossy.
Allow the glaze to cool slightly before pouring it over the cream layer. Spread it evenly using a spatula or tilt the pan gently to cover the surface.
Step 4: Chill the Cake
Cover the cake with plastic wrap and refrigerate for at least 2-3 hours, or until fully set. For best results, chill overnight.
Step 5: Garnish and Serve
Before serving, optionally garnish with extra chopped walnuts, cookie crumbs, or chocolate shavings for added flair.
Slice with a warm knife for clean cuts and serve chilled.