Prep the pan and oven: Heat the oven to 325°F (163°C). Line the bottom of a 9-inch springform pan with parchment and lightly grease the sides.
Make the crust: In a bowl, combine almond flour, chopped pecans, erythritol, cinnamon, and salt.
Stir in melted butter and vanilla until the mixture looks like damp sand.
Press and pre-bake: Press the crust into the pan in an even layer. Bake for 10–12 minutes until set and lightly golden. Cool while you make the filling.
Beat the cream cheese: In a large mixing bowl, beat softened cream cheese on medium speed until smooth and fluffy, about 2 minutes.
Scrape the bowl as needed.
Add sweetener and pumpkin: Beat in erythritol until well blended, then mix in pumpkin puree until smooth.
Finish the filling: Add sour cream, vanilla, spices, and salt. Mix just until combined. Add eggs one at a time on low speed, mixing only until incorporated. Do not overmix.
Prepare a water bath (optional but helpful): Wrap the outside of the springform pan with two layers of foil to prevent leaks.
Place the pan in a large roasting pan and add hot water to reach halfway up the sides. This helps prevent cracks.
Bake: Pour the filling over the crust. Bake at 325°F for 55–70 minutes.
The edges should be set and the center should have a slight wobble.
Cool gently: Turn off the oven, crack the door, and let the cheesecake rest inside for 30 minutes. Then remove from the oven and water bath, and cool on a rack until room temperature.
Chill: Cover and refrigerate for at least 6 hours, ideally overnight. Chilling sets the texture and deepens the flavor.
Make the pecan topping: In a small skillet over medium heat, melt butter. Add pecans, sweetener, cinnamon, and salt.
Toast 3–4 minutes, stirring, until fragrant and glossy. Cool completely.
Finish and serve: Release the cheesecake from the pan. Scatter the cooled pecans on top.
Slice with a hot, clean knife for neat pieces.