Preheat the oven to 350°F (175°C). Place the graham cracker crust on a baking sheet.
In a large mixing bowl, beat the room-temperature cream cheese, granulated sugar, and vanilla extract until smooth and creamy.
Add the eggs and mix just until combined.
Scoop about 1 cup of the plain cheesecake batter into the graham cracker crust and spread it evenly.
Add the pumpkin puree and pumpkin spice to the remaining cheesecake batter. Mix until smooth.
Spoon the pumpkin cheesecake mixture over the plain cheesecake layer.
Smooth the top with a spatula.
Bake for 35–45 minutes, or until the edges are set and the center still has a slight jiggle.
Turn off the oven, crack the oven door, and let the cheesecake rest for about 15 minutes.
Cool at room temperature, then refrigerate for at least 4 hours, or until fully chilled.
Slice and serve with whipped cream, if desired.