In a medium bowl, combine chocolate cookie crumbs, melted unsalted butter, unsweetened cocoa powder, and granulated sugar. Mix until moistened and crumbly. Press into an 8x8 baking dish.

In a large bowl, beat softened cream cheese until smooth. Gradually add powdered sugar, mixing until combined. Fold in whipped heavy cream until fluffy.

Spread the creamy filling evenly over the crust using an offset spatula.

Cover with plastic wrap and refrigerate for at least 4-6 hours, ideally overnight.

In a saucepan over low heat, melt chocolate chips with butter and a splash of milk until smooth.

Pour the warm glaze over the chilled cake, spreading evenly. Allow to cool for 15-20 minutes.

Slice the cake into squares and serve chilled, optionally garnished with whipped cream or fresh berries.