Step 1

Preheat the oven to 325°F. Line an 8×8-inch metal baking pan with foil, leaving an overhang.

Step 2

In a large bowl combine the butter, sugar, cocoa powder, and salt. Stir until well combined, mixture will be thick. Let cool if the butter is still hot. Stir in the vanilla and then the eggs, one at a time, stirring very well after each addition. Stir until the batter is very well blended. Add the flour and stir again until very well blended. Spread into prepared pan.

Step 3

Bake for 15 minutes, or until just starting to set but not fully cooked. Let cool to room temperature then place in the fridge to chill until ready to use while you make the other layers. Maintain 325°F oven temperature if baking cheesecake layer immediately.

Step 4

In a large bowl, use an electric mixer to beat the butter, brown sugar, granulated sugar, salt, vanilla, and milk until smooth, about 2 minutes. On low speed gradually add the flour and beat until combined. Mix in the chocolate chips. Place the dough between two sheets of parchment and roll into an 8-inch square. Refrigerate while you prepare the cheesecake batter.

Step 5

In a large bowl, use an electric mixer to beat the cream cheese and sugar until well combined and smooth. Beat in the eggs, flour, and salt just until incorporated. Pour the cheesecake batter over the brownie layer. Place the cookie dough sheet over the cheesecake batter.

Step 6

Bake at 325°F for about 50 minutes, or until the cheesecake is set and the cookie dough is barely golden but dry. Cool to room temperature before refrigerating for at least 2 hours to chill. Cut into 12 bars before serving. For clean cuts, use a big sharp knife and run it under hot water and wipe it off between slices. Bars can be stored in an airtight container in the fridge for up to 3 days.