This rich and creamy cheesecake with a gorgeous chocolate hazelnut swirl is a showstopper dessert. It's low carb and keto friendly, making it perfect for any occasion.
Preheat the oven to 325F. Wrap the outside bottom and sides of a 9-inch springform pan with foil. Mix the ground hazelnuts, almond flour, melted butter, powdered erythritol, cocoa powder, and salt. Press firmly into the bottom of the pan. Bake for 10 minutes, then let cool.
Beat the cream cheese and powdered erythritol with an electric mixer until very smooth and fluffy, about 3 minutes. Scrape down the sides of the bowl.Add the eggs one at a time, mixing on low speed after each until just incorporated. Mix in the sour cream and vanilla until smooth. Do not overmix.
Make the chocolate hazelnut swirl by melting the dark chocolate and heavy cream together in a small bowl in the microwave in 30-second intervals, stirring between each. Stir in the hazelnut butter and powdered erythritol until smooth. Let cool slightly.
Pour the cheesecake filling over the crust. Drop spoonfuls of the chocolate hazelnut mixture across the surface. Use a toothpick or skewer to drag through the dollops, creating elegant swirl patterns.
Place the springform pan in a larger roasting pan and pour hot water into the roasting pan until it comes about 1 inch up the sides. Bake for 55 to 65 minutes until the edges are set and the center still jiggles gently.
Turn off the oven, crack the door open, and let the cheesecake cool in the oven for 1 hour. Then remove and refrigerate for at least 6 hours or overnight before slicing.
Garnish with chopped toasted hazelnuts and a drizzle of melted sugar-free dark chocolate before serving.