Preheat oven to 350℉. Line a 13x9" light metal baking pan with parchment paper or foil, extending the sides of the paper or foil over the edges of the pan. Spray with cooking spray; set aside.
In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter and stir until moistened and mixture resembles wet sand. Pour the mixture into the bottom of the prepared pan and press it into an even layer. Bake for 10 minutes. Remove from oven, but keep oven on.
While the crust bakes, prepare your cheesecake filling: In the bowl of a stand mixer, cream the cream cheese for about 1 minute with the paddle attachment. Add in the sugar and mix well, followed by the eggs, one at a time, mixing well after each addition. Add in the sour cream, flour, and vanilla extract and mix well, scraping down the bottom and sides of the mixing bowl to ensure no lumps.
Pour the cheesecake filling evenly over the pre-baked crust and smooth out the top. Return to the oven and bake for another 30-35 minutes or until the center appears set and does not jiggle.
While the cheesecake bars bake, prepare your pecan pie topping: In a medium saucepan, melt the butter over medium heat. Add in the corn syrup, heavy cream, brown sugar and mix well. Add in the vanilla extract and pecans and stir well. Allow the mixture to come to a boil and boil, stirring constantly, for about 5 minutes. Remove from the heat and evenly pour over the cheesecake while it is still warm, carefully spreading into an even layer (be gentle as the warm cheesecake will be delicate).
Cool completely at room temperature, then refrigerate to set completely for about 4 hours before cutting into bars.