Preheat oven to 325°F / 160°C. Line a 9-inch springform pan with parchment; grease sides.

Make crust: Mix almond flour + 15 g cocoa + 30 g erythritol. Stir in 60 g melted butter until mixture holds when pressed. Press into bottom of pan. Bake 10 minutes. Cool.

Blend filling: Beat 680 g room-temp cream cheese until smooth (2–3 min). Add 80 g erythritol gradually; blend. Add 80 g cocoa and vanilla; mix on low. Add eggs one at a time, mixing gently after each. Stir in 120 g heavy cream until just combined. Scrape bowl.

Assemble: Pour filling over cooled crust. Tap to release bubbles. Place springform in a roasting pan and add hot water halfway up the pan sides (water bath).

Bake: Bake 50–60 minutes at 325°F until edges are set and center slightly jiggles.

Cool slowly: Turn off oven, crack door, let sit 1 hour. Remove pan, cool to room temp on rack, then refrigerate 6+ hours (overnight best).

Optional ganache: Whisk 60 g warm heavy cream with 15 g cocoa powder and pour over chilled cheesecake. Chill 10–15 minutes.

Run a hot knife around sides before slicing for clean pieces. Serve chilled.