• Arrange your oven rack to the lower position. Preheat your oven to 325°F. Begin boiling water for the water bath.
• Line the bottom of a 9" springform pan with parchment paper. Lightly grease the sides of the pan with non-stick spray or line the sides with more parchment paper. Wrap several layers of heavy-duty aluminum foil around the pan, then tie a slow-cooker oven liner around the pan (recommended) so water doesn't leak into the pan from the water bath.
• Begin boiling water for the water bath.

Make the Graham Cracker Crust:

• Mix the graham cracker crumbs, granulated sugar, and melted butter until evenly combined. Pour the crumb mixture into the prepared pan, spread it around evenly, then use the bottom of a glass or measuring cup to pack it down tightly and evenly in the bottom and slightly up the sides.
• Bake the crust in the preheated oven for 10 minutes while you make the filling.

Make the Filling:

• White chocolate ganache (added to the filling): Add half a cup (3 oz.) chopped white chocolate or chips and 2 tablespoons of heavy cream to a small bowl. Microwave in 30-second intervals, stirring between, until melted and smooth. Set aside to cool slightly.
• In a large bowl or bowl of a stand mixer fitted with a paddle attachment, mix the room temperature cream cheese, granulated sugar, and flour until smooth with no lumps. Add the room temperature sour cream and vanilla extract and mix until smooth. Wipe the sides of the bowl with a rubber spatula, then add the room temperature eggs, one at a time, and mix until just combined after each. Mix until the batter is smooth and stir in the white chocolate ganache.
• Pour the cheesecake filling over the pre-baked crust. Tap the pan on the counter several times to get rid of any trapped air bubbles in the filling. Place the springform pan inside a large roasting pan and very carefully pour the boiling water around it, going up about 2" around the sides of the pan.
• Bake the cheesecake for 1 hour and 10 minutes. Gently shake the pan, if the outside edges are set and there is a 2-3" wobbly center, it's done. If it's still very pale and wobbly all over, keep baking and check on it again in 5 minute-intervals until done.
• Once done, turn the oven off and leave the cheesecake inside with the door cracked for 1 hour. Remove the cheesecake from the oven and the water bath and let cool completely at room temperature for at least 1 hour. Don't remove the sides of the pan.
• Transfer to the fridge, still in the pan and uncovered, to cool and set completely. At least 4 hours, but overnight is best.

White chocolate ganache (poured over the cooled cheesecake):

• Add half a cup (3 oz.) chopped white chocolate or chips and 2 tablespoons of heavy cream to a small bowl. Microwave in 30-second intervals, stirring between, until melted and smooth.
• Pour the ganache over the cheesecake and use an offset spatula to spread it out evenly. Place the cheesecake in the fridge for about 10 minutes to set the ganache.