Line an 8-inch square baking pan with parchment paper, ensuring there is an overhang on two sides for easy removal.

In a medium bowl, combine the chocolate cookie crumbs, cocoa powder, and melted butter until the mixture resembles wet sand.

Press the crumb mixture firmly and evenly into the bottom of the prepared pan; refrigerate while preparing the filling.

In a large mixing bowl, beat the softened cream cheese and granulated sugar together until smooth and creamy.

Add the vanilla extract and cooled melted chocolate to the cream cheese mixture, beating until fully incorporated and uniform in color.

In a separate chilled bowl, whip the 1 cup of heavy cream until stiff peaks form.

Gently fold the whipped cream into the chocolate cheesecake mixture using a spatula until no white streaks remain.

Stir in the chopped brownie bites until they are evenly distributed throughout the batter.

Spread the cheesecake filling over the chilled crust and smooth the top with an offset spatula.

Prepare the ganache by heating 1/4 cup heavy cream until simmering, then pouring it over 1/2 cup chocolate chips; let sit for 3 minutes before stirring until glossy.

Drizzle the ganache over the cheesecake and garnish with extra brownie pieces if desired.

Refrigerate for at least 4 hours, or preferably overnight, until the cheesecake is completely set before lifting from the pan and slicing.