Preheat oven to 325F. In the bottom of a 9-inch springform pan, combine hazelnut meal, cocoa powder and sweetener. Stir in melted butter until well combined. Press crumb mixture firmly and evenly into bottom of pan.
Bake 10 minutes, then remove from oven and let cool while working on the filling.
Reduce oven temperature to 300F.
In a large bowl, beat cream cheese with sweetener until well combined. Beat in eggs, one at a time, scraping down sides of bowl and beaters as needed.
Beat in heavy cream and vanilla until mixture is smooth and well combined.
Brush the sides of the pan with melted butter or spray with coconut oil spray.
Pour half the cheesecake batter over the cooled crust and drizzle with half of the Nutella. Swirl with a knife. Repeat with remaining batter and remaining Nutella.
Bake cheesecake for about 1 hour and 20 minutes to 1 hour and 30 minute, until filling is mostly set but just jiggles slightly in the center.
Remove from oven and let cool completely in the pan. Run a sharp knife around the edge and release the sides. Cover tightly with plastic wrap and refrigerate 2 to 3 hours.
Serves 16. Each serving has 6.09 g of carbs and 2.4 g of fiber. Total NET CARBS = 3.69 g.Food energy: 318kcal Saturated fatty acids: 12.20g Total fat: 29.37g Calories from fat: 264 Cholesterol: 94mg Carbohydrate: 6.09g Total dietary fiber: 2.40g Protein: 6.59g Sodium: 171mg