Position one oven rack on the bottom shelf and another in the center. Preheat your oven to 325°F (165°C). Line the bottom of a 9-inch springform pan with parchment paper.
In a medium bowl, stir together the graham cracker crumbs, granulated sugar, and 1 teaspoon of ground cinnamon. Pour in the melted butter and mix until the crumbs are evenly moistened.
Press the crumb mixture firmly into the bottom and halfway up the sides of the prepared springform pan. Bake on the center rack for 8 minutes, then set aside to cool.
In a large bowl, beat the 32 oz (900g) of cream cheese and the brown sugar on low speed until smooth. Mix in the sour cream, flour, salt, and 2 teaspoons of vanilla extract.
Add the eggs one at a time, mixing on low speed just until each egg disappears. Scrape down the sides and bottom of the bowl with a rubber spatula to ensure an even mixture.
Pour half of the plain cheesecake batter over the cooled crust. Gently fold the 2 tablespoons of ground cinnamon into the remaining half of the batter in the bowl.
Spoon the cinnamon batter over the plain batter in the pan. Use a knife to gently swirl the two batters together without scraping the crust.
Place a large baking dish filled with 2 inches of boiling water on the bottom oven rack. Place the cheesecake on the center rack directly above the water. Bake for 65 to 70 minutes. The edges will look firm, but the center should still jiggle slightly. The internal temperature of a baked dish containing eggs must reach 160°F (71°C) for food safety.
Turn off the oven and crack the door open. Leave the cheesecake inside for 1 hour. After 30 minutes, run a thin knife around the edge of the pan to loosen the sides. Remove from the oven, cool to room temperature, then chill in the refrigerator for at least 6 hours.
To make the frosting, beat the 3 oz (85g) of cream cheese and 3 tablespoons of butter until smooth. Stir in the powdered sugar and 1/2 teaspoon of vanilla extract until creamy. Spread over the chilled cheesecake before slicing.