Preheat the oven to 325 degrees. Line a 9x13 baking pan with parchment paper.
In a large bowl add the softened butter, brown sugar and granulated sugar, using a hand mixer beat until combined .
Add in the egg, extra egg yolk, and vanilla and mix until combined.
Add in the flour, baking soda and salt and mix just until everything comes together.
Add in the chocolate chips and mix until incorporated.
Add 1/2 of the cookie dough into the bottom of the baking pan and press into an even layer and set aside.
Cheesecake Layer
In a large bowl, add the softened cream cheese, sour cream, powdered sugar, egg, and vanilla, and using the hand mixer, mix until creamy.
Spread the cream cheese mixture evenly over the chocolate chip cookie dough.
Press the remaining cookie dough into disks and place it on top of the filling. You won't have enough to cover it.
Bake for 30-35 minutes or until golden brown and the cheesecake is set.
Let cool completely, then chill for at least 2 hours before slicing.
Notes
Don’t overbake the bars. The center should still have a slight jiggle when removed from the oven since the cheesecake layer will continue to set as it cools.
Store leftovers covered in the refrigerator for up to 5 days.
These bars freeze well. Wrap individual bars tightly and freeze for up to 2 months. Thaw overnight in the refrigerator before serving.