Preheat oven to 325°F (165°C). Line an 8x8-inch metal baking pan with parchment paper, leaving an overhang on the sides for easy removal.

Mix graham cracker crumbs, sugar, melted butter, and cinnamon. Press firmly into an even layer in the bottom of the pan. Bake for 8 minutes, then let cool slightly.

In a large bowl, beat softened cream cheese and sugar with an electric mixer on medium-low until smooth and completely lump-free. Beat in eggs one at a time, followed by vanilla extract.

Reserve 1/2 cup of the plain cheesecake batter. To the remaining batter, whisk in pure pumpkin puree and pumpkin pie spice until fully combined and silky.

Pour pumpkin batter over the pre-baked crust. Drop dollops of the reserved plain cheesecake batter over top. Use a butter knife or toothpick to gently swirl the batters together in figure-eight patterns.

Bake at 325°F for 35 to 40 minutes until edges are set but center has a slight gentle jiggle. Turn off oven, crack door open, and cool for 30 minutes. Refrigerate for at least 4 hours before slicing into clean squares with a warm sharp knife.