01 - Preheat oven to 325°F. Lightly grease a 9-inch springform pan and line the bottom with parchment paper.
02 - In a medium bowl, combine almond flour, powdered erythritol, melted butter, cinnamon, and salt until the mixture resembles damp sand. Press the mixture firmly and evenly into the bottom of the prepared pan. Bake for 10 to 12 minutes until lightly golden. Remove from the oven and set aside to cool.
03 - In a small saucepan, combine chopped rhubarb, water, and powdered erythritol. Bring to a simmer over medium heat and cook for 8 to 10 minutes, stirring occasionally, until the rhubarb softens and the mixture thickens into a compote. Remove from heat, stir in the vanilla extract, and let cool completely.
04 - In a large bowl, beat the softened cream cheese and powdered erythritol with a hand or stand mixer until completely smooth. Add the eggs one at a time, mixing thoroughly after each addition. Blend in the sour cream, vanilla extract, lemon zest, and heavy cream until the batter is fully incorporated and creamy.
05 - Pour the cheesecake filling over the cooled crust, spreading evenly. Drop spoonfuls of the cooled rhubarb compote across the surface of the batter. Use a knife or skewer to gently drag through the compote and filling, creating a marbled swirl effect. Avoid over-mixing to maintain distinct ribbons.
06 - Bake for 40 to 45 minutes, or until the edges are set and the center retains a slight jiggle. Turn off the oven, crack the door open, and let the cheesecake rest inside the cooling oven for 1 hour to prevent cracking.
07 - Remove the cheesecake from the oven and allow it to cool to room temperature. Transfer to the refrigerator and chill for at least 2 hours before slicing into 12 even pieces and serving.