Preheat the oven to 350° Fahrenheit. Grease a 9-inch springform pan. If baking with a water bath, wrap the outside and bottom of the pan tightly with aluminum foil to prevent leaks.

In a medium bowl, stir together the graham cracker crumbs, melted butter, ¼ cup brown sugar, and cinnamon until evenly moistened. Press the mixture firmly into the bottom and slightly up the sides of the prepared pan.

In a stand mixer or with a hand mixer, beat the cream cheese, granulated sugar, and remaining brown sugar on medium-high speed for 4 minutes until smooth and creamy.

Add the pumpkin puree, eggs, and sour cream. Beat on medium speed just until combined, then add the flour, pumpkin pie spice, and salt. Mix on medium speed again just until combined, without overbeating.

Pour the filling over the crust and smooth the top. For a water bath, set the springform pan into a large roasting pan or deep skillet. Carefully pour in 2 inches of boiling water around the outside of the pan.

Bake for 60 minutes. The edges should be set while the center remains slightly jiggly.

Turn the oven off, crack the door, and leave the cheesecake inside for 60 minutes.

Remove from the oven and cool at room temperature for 30 minutes. Cover and refrigerate for at least 4 hours or overnight.

Slice, garnish with whipped cream and a sprinkle of cinnamon if desired, and serve cold.