TO MAKE THE CRUST - Preheat the oven to 350 F.  Then, line with parchment paper and spray with non-stick spray on a 9x13 inch baking pan and set aside. Next, combine graham cracker crumbs, light brown sugar, cinnamon, finally chopped pecans and melted butter in a medium sized dish. Put the mixture in an already prepared pan, spread it evenly and then press with a measuring cup to make solid and even layer. Bake for 8 minutes and then cool completely before adding a cheesecake layer. 

TO MAKE THE CHEESECAKE LAYER - In a medium sized dish, beat cream cheese, sugar and vanilla at medium-low speed until smooth, then add one egg at a time and continue beating until combined. Next, add flour and sour cream and mix some more to combine all the ingredients. Do not overmix!  Then, put 5 cups of  cheesecake filling over the graham cracker crust and spread evenly. Leave it in the freezer for 5 minutes. Meanwhile, prepare a pumpkin cheesecake layer.  

TO MAKE THE PUMPKIN CHEESECAKE LAYER - Fold pumpkin puree, cinnamon, nutmeg and ginger  in the remaining cheesecake filling. Mix it until combined and then spread evenly over the cheesecake layer and bake for 30 minutes at 350 F.  Meanwhile, prepare streusel topping. 

TO MAKE STREUSEL TOPPING - combine flour, rolled oats, light brown sugar, salt, cinnamon, nutmeg and pecans, then add melted butter and mix until well combined. The mixture should be crumbly. After 30 minutes, take the cheesecake out of the oven and sprinkle it with streusel. Bake the cake for another 40-50 minutes or until the edges are solid and slightly inflated and the center dented and swaying when you shake the pan up.

When the cake is ready, turn the oven off and leave the cheesecake in it, with the door open for an hour, then leave it to cool completely at room temperature. Finally, leave the cake covered in the fridge for at least 6 hours, possibly for 24 hours. Cut the cake into cubes before serving with caramel sauce or whipped topping.