Preheat oven to 325F (160C) and line a 9×9" (22x22cm) baking pan with parchment paper (optional, but helps prevent cracks and makes removing from the pan and slicing easier).

In a mixing bowl, stir together graham cracker crumbs and sugars. Add melted butter and stir until mixture is combined and resembles wet sand. Pour into prepared pan and press evenly across the bottom of the pan. Set aside (do not bake yet).

In a large mixing bowl, combine softened cream cheese, granulated and brown sugar and use an electric mixer (or paddle attachment on stand mixer) on medium-speed to stir until mixture is smooth and creamy and no lumps remain.

Add sour cream and vanilla extract and stir until combined.

Add eggs, one at a time, stirring on low-speed until just combined before adding the next egg. Scrape the sides and bottom of the bowl with a spatula to ensure batter is uniform.

Measure out about 1 ½ cups of cheesecake batter and pour into a separate mixing bowl. To this, add the pumpkin puree and pumpkin spice and stir until combined.

Alternate dollops of the two batters over the prepared crust then swirl with a knife. Transfer to 325F (160C) oven and bake for 40-45 minutes (see note if you are not using a metal baking pan) or until cheesecake is mostly set but center is still slightly jiggly. Allow to cool to room temperature, then transfer to refrigerator and chill for at least 6 hours, preferably overnight before cutting and serving.