Start by preheating the oven to 350F, then line an 8x8 baking pan with parchment paper.
In a large bowl, mix the brownie mix, egg, water, vanilla extract, vegetable oil, and chocolate chips together until combined.
Pour ⅓ of the brownie mixture into the prepared baking pan and spread on the bottom of the pan and set aside.
In a different large bowl, whisk the cream cheese and sugar together until combined. Add in the egg yolk, the pumpkin puree and the pumpkin pie spice and mix until smooth and creamy.
Pour the pumpkin cheesecake layer on the brownie layer and gently spread evenly.
Top the pumpkin cheesecake with the remainder of the brownie batter (make sure to place a few dollops throughout the whole pan because you will need to spread it throughout and that will make the job a lot easier)
Using a spatula, gently spread the brownie batter to cover the cheesecake layer and bake in the preheated oven for 44-45 minutes.
Let the brownies cool down fully before slicing into them and enjoying them.