Prep the pan and oven. Heat the oven to 325°F (163°C). Line a 9-inch springform pan with parchment on the bottom and lightly grease the sides. Wrap the outside with foil if your pan tends to leak.

Mix the brownie base. In a bowl, whisk almond flour, cocoa powder, granulated sweetener, baking powder, and salt. In another bowl, whisk eggs, melted butter, and vanilla. Stir the wet into the dry. Fold in melted sugar-free chocolate if using. The batter will be thick.

Spread the brownie layer. Press the brownie batter evenly into the prepared pan. Use a spatula to smooth the surface. Bake for 10 minutes to set slightly, then remove and cool for 5 minutes.

Beat the cheesecake batter. In a large bowl, beat softened cream cheese with powdered sweetener until smooth and fluffy, about 1–2 minutes. Add pumpkin puree, vanilla, spices, and salt. Beat again until fully combined. Add eggs one at a time, mixing on low until just incorporated. Do not overbeat.

Layer and smooth. Pour the pumpkin cheesecake batter over the partially baked brownie base. Tap the pan gently on the counter to release air bubbles. Smooth the top with an offset spatula.

Bake low and slow. Place the pan on the middle rack and bake for 45–55 minutes, until the edges are set and the center has a slight wobble. If the top browns too quickly, tent loosely with foil for the last 10–15 minutes.

Cool gradually. Turn off the oven, crack the door, and let the cheesecake rest inside for 15 minutes. Transfer to a cooling rack and cool to room temperature. Run a knife around the edge to loosen.

Chill to set. Cover and refrigerate at least 4 hours, preferably overnight. This step is crucial for clean slices and the best texture.

Finish and serve. If you like, sprinkle sugar-free chocolate chips on top before chilling or add a dollop of whipped cream when serving. Slice with a hot, clean knife for neat edges.