Preheat your oven to 350°F (175°C). Grease a 9-inch springform pan, line the bottom with parchment paper, and grease again for easy removal. Bake the all-purpose flour on a baking sheet for 5 minutes and let it cool.

In a large mixing bowl, beat the unsalted butter and white granulated sugar until light and creamy. Add vanilla extract, egg, and egg yolk, mixing until fully combined. Incorporate the dry ingredients along with Christmas sprinkles, then spread the dough into the prepared pan. Bake for 25-30 minutes until edges are golden.

Combine all-purpose flour and salt in one bowl. In another bowl, beat softened butter and sugar until smooth. Stir in vanilla and milk, then add the flour mixture along with Christmas sprinkles. Roll into balls and freeze.

Lower the oven temperature to 325°F (160°C). Beat cream cheese and sugar until creamy. Add sour cream, heavy cream, and vanilla, mixing well. Incorporate eggs one at a time. Fold in frozen cookie dough balls.

Pour the cheesecake mixture over the baked crust. Place in a water bath and bake for 80-90 minutes, until edges are set. Cool in the oven for 1 hour, then refrigerate for at least 6 hours.

Heat heavy cream in a saucepan until steaming, then pour it over white chocolate chips. Let sit for 5 minutes, then stir until smooth. Pour ganache over chilled cheesecake and freeze for 10 minutes.

Once the ganache is set, remove the cheesecake from the pan. Top with remaining cookie dough balls and sprinkles. Slice and serve chilled.