Preheat the oven to 325°F (163°C). Grease the springform pan or line the bottom with parchment paper for easier removal.
In a mixing bowl, combine almond flour, cocoa powder, erythritol, and melted butter. Mix until it forms a crumbly dough.
Press the mixture evenly into the bottom of the springform pan to create the crust.
In a separate bowl, beat the cream cheese with an electric mixer until smooth and creamy.
Add in the pumpkin puree, eggs, vanilla extract, cinnamon, nutmeg, ginger, salt, and sour cream. Mix until fully incorporated and smooth.
Pour the pumpkin cheesecake filling over the crust in the springform pan, smoothing the top with a spatula.
Bake in the preheated oven for 60 minutes, or until the center is set but still slightly jiggly.
Turn off the oven, crack the door open, and let the cheesecake cool inside for an hour to prevent cracking.
Remove the cheesecake from the oven and let it cool to room temperature before refrigerating for at least 4 hours or overnight for better flavor.
Serve chilled and enjoy your delicious keto pumpkin cheesecake!