Get Ready: Preheat your oven to 350°F. Line the bottom of a 9-inch springform pan with parchment paper, then give the inside a quick spray with nonstick cooking spray. Wrap the outside bottom and sides of the pan tightly with 2-3 layers of aluminum foil to keep water out.
Make the Crust: In a food processor, combine the almond flour, sugar substitute, and melted butter. Pulse until you have fine crumbs.
Press the Crust: Transfer these crumbs into your prepared pan. Use a flat-bottomed glass to press the crumbs firmly onto the bottom and a little up the sides of the pan. Bake this crust for 10-12 minutes, then let it cool completely on a wire rack.
Whip the Filling Base: In a stand mixer (or a large bowl with an electric mixer), beat the softened cream cheese for 2-3 minutes until it's super smooth and lump-free. Add your sugar substitute and blend for another 2 minutes, scraping down the sides of the bowl as needed.
Add Eggs & Flavor: Mix in the eggs one at a time, making sure each is fully incorporated before adding the next. Scrape the bowl after each addition. The mixture should be wonderfully smooth and creamy. Stir in the lemon zest and vanilla extract just until combined.
Bake the Cheesecake: Pour this creamy filling into your cooled crust. Place the springform pan into a larger roasting pan. Carefully pour boiling water into the roasting pan until it comes halfway up the sides of the cheesecake pan.
Cool Down (Slowly!): Bake for 50-60 minutes, or until the edges look set but the center still has a slight wiggle. Turn off the oven, prop the door open with a wooden spoon, and let the cheesecake cool in the oven for 2 hours. Then, remove it from the water bath and cool completely on a rack.
Chill Out: Once fully cooled, transfer the cheesecake to the fridge and chill for at least 8 hours, or ideally, overnight. This is key for a perfect slice!
Whip Up the Jam: In a small saucepan, combine the raspberries, water, sugar substitute, and xanthan gum. Bring to a boil over medium heat, stirring constantly, for 1 minute. Take it off the heat, stir in the vanilla, and let it cool completely before chilling for at least 1 hour.
Serve Sweetness: Once the cheesecake is chilled, spread your lovely raspberry jam over the top and get ready to enjoy this delightful, healthy treat!