Preheat oven to 350°F (175°C). Line a 9 x 13-inch baking pan with parchment paper, leaving an overhang for easy removal.
In a large bowl, combine chocolate cookie crumbs and melted butter. Mix until well combined. Press mixture into the bottom of the prepared pan to form a crust. Set aside.
In a separate large mixing bowl, beat softened cream cheese and sugar on medium speed until smooth and creamy.
Add eggs one at a time, making sure each is fully incorporated before adding the next.
Mix in cocoa powder, vanilla extract, and salt until well combined.
Stir in chocolate chips gently, reserving a small handful for topping, if desired.
Pour the cheesecake batter over the crust in the pan. Spread evenly with a spatula.
If desired, sprinkle reserved chocolate chips on top for texture.
Bake for 30 minutes, or until the edges are set but the center still slightly jiggles.
Turn off the oven and let the bars cool in the oven for 1 hour. Then transfer to a wire rack to cool completely.
Refrigerate for at least 4 hours or overnight before cutting into 24 bars.
Cut into bars and serve chilled.