Make the Crust

1. Preheat oven to 325°F (163°C). Line a 9-inch (23cm) springform pan with parchment paper in the bottom and grease the sides.
2. Combine the crust ingredients in a small bowl. Press the mixture into the bottom and up the sides of the springform pan.
3. Bake the crust for 10 minutes, then set aside to cool.
4. Cover the outsides of the pan with aluminum foil so that water from the water bath cannot get in (see how I prepare my pan for a water bath). Set prepared pan aside.

Make the Cheesecake

1. Reduce oven temperature to 300°F (148°C).
2. In a large bowl, beat the cream cheese, sugar and 3 tablespoons (24g) of flour on low speed until well completely combined and smooth. Be sure to use low speed to reduce the amount of air added to the batter, which can cause cracks. Scrape down the sides of the bowl.
3. Add the sour cream and vanilla extract and mix on low speed until well combined.
4. Add the eggs one at a time, mixing slowly to combine after each addition. Scrape down the sides of the bowl as needed to make sure everything is well combined.
5. Add the sprinkles and gently stir to combine. Set aside.
6. Pour the full can of rainbow chip frosting for the cheesecake filling into a medium sized bowl. Add the remaining 6 tablespoons (48g) of flour and stir until well combined. The flour keeps the frosting from dissolving into the cheesecake while it bakes.
7. Spread the frosting evenly onto the bottom of the cooled crust.
8. Layer half a cup of mini vanilla wafers over the frosting, placing them so that they form an even layer.
9. Spoon about half of the cheesecake filling over the vanilla wafers and spread into an even layer.
10. Add the remaining half a cup of mini vanilla wafers in an even layer.
11. Spoon the rest of the filling over the vanilla wafers and spread into an even layer.
12. Place the springform pan inside another larger pan. Fill the outside pan with enough warm water to go about halfway up the sides of the springform pan. The water should not go above the top edge of the aluminum foil on the springform pan.
13. Bake for 1 hour 10 minutes. The center should be set, but still jiggly.
14. Turn off the oven and leave the door closed for 30 minutes. The cheesecake will continue to cook, but slowly begin to cool as well.
15. Crack the door of the oven for 30 minutes to allow the cheesecake to continue to cool slowly. This process helps prevent cracking.
16. Remove the cheesecake from the oven and water bath wrapping and refrigerate until firm, 5-6 hours or overnight.
17. Remove the cheesecake from the springform pan and place on a serving dish.

Make the Topping

1. To make the blue buttercream, add the butter to a mixer bowl and beat until smooth.
2. Add half of the powdered sugar and mix until well combined and smooth.
3. Add the vanilla extract and one tablespoon of cream or water and mix until well combined and smooth.
4. Add the remaining powdered sugar and mix until well combined and smooth. Add additional cream or water, as needed, to get the right consistency of frosting.
5. Color the frosting blue with the blue gel icing color. Set aside.
6. Spread some of the second can of rainbow chip frosting onto the top of the cheesecake, leaving some space around the outer edge. You can add as much as you like. I used most, but not all, of the can.
7. Add the blue frosting to a piping bag with a piping tip (I used Ateco 847) and pipe around the outer edge of the cheesecake.
8. Decorate cheesecake with additional sprinkles and some of the cookies from a Dunkaroo package.