01 - Preheat oven to 325°F. Lightly grease a 9-inch springform pan with butter and line bottom with parchment paper circle.
02 - Combine crushed graham crackers, melted butter, brown sugar, and cinnamon in medium bowl until mixture resembles wet sand. Press firmly and evenly into bottom of prepared pan using measuring cup or flat bottom of glass.
03 - Bake crust for 10 minutes until fragrant and set. Remove from oven and place on wire rack while preparing filling.
04 - Beat softened cream cheese and granulated sugar in large mixing bowl with electric mixer on medium speed until completely smooth and creamy, about 3 minutes, scraping bowl frequently.
05 - Add pumpkin purée, sour cream, flour, pumpkin pie spice, vanilla extract, and salt to cream cheese mixture. Beat on low speed until fully incorporated.
06 - Add eggs one at a time, beating on low speed after each addition just until blended. Avoid overmixing to prevent cracks. Scrape down sides and bottom of bowl.
07 - Pour filling over pre-baked crust. Tap pan gently on counter several times to release air bubbles. Bake for 50-60 minutes until edges are set and center jiggles slightly like gelatin.
08 - Turn off oven and crack door open slightly. Leave cheesecake inside for 1 hour to prevent sudden temperature change. Remove to wire rack and cool completely to room temperature, about 2 hours.
09 - Refrigerate cheesecake uncovered for at least 4 hours or overnight until completely cold and firm throughout.
10 - Whip cold heavy cream, powdered sugar, and vanilla extract with electric mixer or whisk until soft peaks form that hold their shape when beaters are lifted.
11 - Release springform ring and place cheesecake on serving plate. Spread or pipe whipped cream over top. Dust generously with ground cinnamon. Slice and serve chilled.