Preheat oven to 350°F. Line the bottom of a 9-inch springform pan with parchment paper. Spray the inside of the pan with nonstick cooking spray. Tightly wrap the outside bottom and sides of the springform pan with two to three layers of aluminum foil.
Place almond flour, sugar substitute, and butter and pulse until combined.
Transfer the crumbs into the prepared pan. Press them down with a flat bottomed glass, and along the sides on the pan. Bake for 10-12 mins, then remove pan to a cooling rack to cool completely.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using an electric mixer, beat cream cheese for 2-3 mins until smooth, working out all the lumps. Add the sugar substitute and blend for another 2 mins. Scrape down the sides of the bowl.
Mix in the eggs, one at a time, until incorporated, scraping down the sides of the bowl after each addition. The mixture should be smooth and creamy. Add in the zest and vanilla and mix until just incorporated.
Pour the filling into the cooled crust. Place pan into a roasting pan and place it in the oven. Pour boiling water into the larger pan until halfway up the sides of the springform pan.
Bake 50 – 60 mins, until the edges will appear to be set, but the center slightly jiggles. Turn off the oven and crack the oven door open with a wooden spoon. Allow the cheesecake to cool in the oven for 2 hrs then remove it from the water bath and place on a cooling rack. Once the cake is completely cooled, refrigerate for at least 8 hrs, up to overnight.
In a small saucepan, combine raspberries, water, sugar substitute, and xanthan gum. Bring to a boil over medium heat, stirring constantly. Boil the mixture for 1 min, then remove from heat and stir in vanilla. Let cool completely then chill for 1 hr before spreading over the cooled cheesecake.