Prepare the brownie batter according to the instructions on the back of the box.
Pour batter into a 9x13 inch pan and back according to the instructions on the back of the box for a 9x13 inch pan. Set the timer to 5 minutes less than the max baking time.
While the brownies bake add the cream cheese, sugar, and vanilla to the bowl of the stand mixer and mix together using the paddle attachment.
Add the sour cream and continue to mix.
Turn the mixer speed to low and add the eggs one at a time mixing until they are just blended into the mixture. Do not overmix.
As the brownies come out of the oven pour the cheesecake mixture over the brownies and use a spatula to make sure it covers the entire surface.
Place the cheesecake brownies back in the oven and continue to bake at 350 degrees F for 40 minutes, or until the edges are set and the center just has a slight jiggle to it.
Remove the pan from the oven and let the cheesecake cool completely (approximately 1 hour).
Cover the cooled cheesecake brownies and place them in the refrigerator for at least 4 hours, preferably overnight.
After chilling remove the cheesecake brownies from the fridge and begin making your pecan pie filling.
Place all of the pecan pie filling ingredients except for the pecans in a medium saucepan and cook over medium heat , stirring constantly. The filling will begin to bubble and thicken. Keep cooking for 35 minutes.
Add the chopped pecans and continue cooking for another 5 minutes then remove from the heat and let cool in the saucepan for 10 minutes.
Spread the pecan pie filling over the cheesecake brownies and place in the refrigerator to cool completely (approximately 1 hour).
Cut and serve.