In a medium pot, put 1 cup of rice and water to boil. When water has completely evaporated, remove the pot from stove, add 6 tablespoons of sugar, 1 tablespoon vanilla sugar and cover with a lid. Leave on a side.
Line the baking sheet with baking paper.
Prepare the Oreo crust by crushing the Oreos and mixing with 2 tablespoons of melted butter (you can use a food processor if you want very fine crumbs; I like a bit more crunchiness in my crust so I crushed the Oreos with a fork which is more time consuming and it also requires some physical effort). Place the Oreo crust in the prepared baking sheet and lightly press with a spoon to form an even layer. Keep in the fridge while following the next steps.
Place the grated pumpkin in a skillet with 1 tablespoon of butter and 3 tablespoons of sugar; cook until pumpkin gets soft. Add a tablespoon of cinnamon when almost ready.
Crush the butter biscuits (or use a food processor) and combine with the pumpkin cinnamon mixture. Mix well until all biscuits are well coated.
Place over the Oreo crust and using a wet tablespoon, form an even layer.
Heat the oven at 350 F.
Beat 2 eggs and mix with 6 tablespoons of sour cream. Pour ? of the mixture over rice and blend well. Pour the rice mixture over the pumpkin and Oreo crusts and spread evenly. Pour the remaining eggs sour cream mixture and spread evenly using a spoon; don’t press into the rice mixture.
Place the baking sheet in the middle of your oven and bake until golden (approximately 30 minutes). Keep an eye on the oven if it tends to burn, you may need to bake for less than 30 minutes.
Enjoy your delicious Pumpkin Rice Pudding Bars with a bit of salted caramel sauce or a dollop of whipped cream.