Line a 9"x 13" pan with aluminum foil and set aside.
In a medium bowl stir together graham cracker crumbs, sugar and butter.
Press crust mixture into the prepared pan and bake in the oven for 10 minutes.
Meanwhile, in a large bowl or stand mixer, beat the cream cheese until smooth.
Add in the sugar and vanilla extract and beat again until combined.
Add in the eggs one at a time, mixing well after each addition.
Lastly add in the sour cream, mix until combined.
Fold in the chopped Oreo cookies and pour into the crust, spreading evenly.
Bake in the oven for 35-40 minutes until the center is almost set, remove from the oven and let cool on the countertop completely.
Cover and refrigerate for 4 hours to set.
Remove from the refrigerator then cut into bars and top with whipped topping and halved Oreo cookies, if desired.
Notes
The bars need to cool completely on the countertop before placing in the refrigerator.
Make sure that you chill for at least 4 hours so the cheesecake has time to set up.
These cheesecake bars can be frozen.
You will find chocolate graham crackers near where all the other graham crackers are in your grocery store (typically near the cookies or sometimes in the baking aisle.) You will need to crush up those chocolate graham crackers into crumbs to use for this recipe. About 2 sleeves should do it.