1. Preheat oven to 350 degrees and prepare a 9 inch square pan with aluminum foil that goes up the sides. You can use the aluminum foil to lift the bars out of the pan when done.
2. Cream butter and sugars together until light and fluffy, about 3-4 minutes.
3. Mix in egg and vanilla extract.
4. Combine flour, baking soda and salt in a medium sized bowl.
5. With the mixer on low speed, add flour mixture to butter mixture.
6. Stir in 1 cup of chocolate chips.
7. To make the cheesecake filling, beat the cream cheese and sugar together until smooth.
8. Add the egg and mix until smooth.
9. Add the cocoa, vinegar and red color and mix until smooth.
10. Spread just over half of the cookie dough into an even layer in the bottom of the pan.
11. Spread cheesecake mixture evenly over cookie base.
12. Crumble the remaining cookie dough on top of the cheesecake, then sprinkle with remaining 1/4 cup of chocolate chips.
13. Bake for 25-28 minutes. Edges should be lightly browned, center may still be a bit jiggly but will firm as it cools.
14. Allow to cool completely before slicing. Store in covered container in refrigerator.