Preheat oven to 350 °F (175 °C). Line an 8×8-inch baking pan with parchment paper.
Make the crust: Mix almond flour, erythritol, cinnamon, and melted butter until crumbly. Press into the bottom of the pan and bake 8 minutes. Let cool slightly.
Prepare cheesecake layer: Beat cream cheese and erythritol until smooth. Add eggs, sour cream, and vanilla; mix until creamy.
Make pumpkin mixture: In a small bowl, stir together ⅔ cup of the cheesecake batter with pumpkin purée and spices.
Assemble: Pour remaining plain cheesecake batter over crust, then spoon pumpkin mixture on top and swirl with a knife.
Bake 30–35 minutes, until the center is set but slightly jiggly.
Cool completely, then refrigerate at least 3 hours before slicing into bars.