Combine blueberries in a small saucepan with the sugar substitute and lemon zest. Bring to a boil then let it simmer in low/medium heat for 10 minutes. Make sauce smooth with an immersion blender then set aside to cool.
Preheat the oven to 175°C.
Butter a 20 cm springform pan and put parchment paper at the base.
Melt the butter for the crust and on medium heat until nutty scent.
Remove from the heat and add the almond flour, vanilla extract and the sugar substitute.Mix together and press into the base of the spring form pan.
Bake the dough crust for 8 minutes until it turns light golden then set aside.
In a mixing bowl, mix together the cream cheese, heavy cream, lemon zest, eggs, vanilla and the sugar substitute.Mix well and pour over the baked crust.
Put the blueberry sauce all around the cheesecake in little amounts. Take chop stick and swirl it back and forth until you've created a beautiful design.
Increase the oven to 200°C and bake the mixture for 15 minutes. Lower the heat to 110°C and bake for another 45 minutes.
Turn off the oven and let it cool inside the oven. Then let it rest in the fridge at least 4 hours.
Serve with fresh blueberries.
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.