Make the crust: In a bowl mix together almond flour, cocoa powder, melted butter, and sweetener until crumbly. Press out evenly onto the bottom of a 10-inch springform pan and bake at 325°F (160°C) for 10 minutes. Let it cool completely.
Make the filling: Beat softened cream cheese and sweetener together until smooth. Beat in eggs, one at a time, just until combined, being careful not to overbeat. Gently mix in sour cream, vanilla, and melted sugar-free chocolate. Blend until creamy.
To bake the cheesecake: Pour the filling over the cooled crust and spread evenly. Place the pan on a baking sheet and bake for 50–55 minutes, until set at the edges but with a slight jiggle in the centre.
Cool, then chill: Allow the cheesecake to cool at room temperature, then refrigerate for at least 4 hours or overnight before slicing and serving with whipped cream or berries.
