Preheat oven to 325 degrees F. Line an 8x8" baking pan with foil, extending the sides of the foil over the edges of the pan. Mist the foil with cooking spray and set aside.
In a medium bowl, stir together the finely crushed Oreo crumbs and the melted butter until combined and moistened. Press into the prepared pan in an even, single layer and bake for approx. 12 minutes. Remove from the oven but keep the oven on.
While crust bakes, prepare your filling. In the bowl of a stand mixer, combine the cream cheese and sugar with the paddle attachment and beat on medium for about 2 minutes or until combined and fluffy. Add in the eggs, one at a time, beating very well after each addition. Beat in the vanilla and sour cream for about 1 minute or until the cheesecake is very light and smooth. Beat in the remaining coarsely crushed Oreo Cookies.
Spread the mixture into the baking dish and smooth out the top. Bake for approx. 35-40 minutes or until the edges are set, the top is very light golden brown and the center is just about set and only a little bit jiggly. Cool completely at room temperature and then once cool, refrigerate for at least 3 hours, preferably overnight, before cutting into bars. Drizzle the room temperature hot fudge on top of the bars just before serving.