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 firmly and evenly into the bottom of the prepared pan. Bake for 10 to 12 minutes until just golden around the edges. Remove from oven and set aside to cool.
03 - While the crust cools, combine chopped rhubarb, water, and powdered erythritol in a small saucepan. Bring to a gentle simmer over medium heat and cook for 8 to 10 minutes, stirring occasionally, until the rhubarb softens and the mixture thickens to a jam-like consistency. Remove from heat, stir in vanilla extract, and let cool completely.
04 - In a large mixing bowl, beat softened cream cheese and powdered erythritol with a hand or stand mixer until completely smooth and free of lumps. Add eggs one at a time, mixing thoroughly after each addition. Blend in sour cream, vanilla extract, lemon zest, and heavy whipping cream until fully incorporated and silky.
05 - Pour the cream cheese filling over the cooled crust, spreading evenly. Drop spoonfuls of the rhubarb compote across the surface of the batter. Using a knife or skewer, gently drag through the compote dollops to create a marbled swirl pattern throughout the cheesecake.
06 - Bake on the center rack for 40 to 45 minutes, or until the edges are set and the center has a slight jiggle when gently shaken. Turn off the oven, crack the door open, and allow the cheesecake to cool gradually inside the oven for 1 hour to prevent cracking.
07 - Transfer the cheesecake from the oven to a wire rack and cool to room temperature. Refrigerate for at least 2 hours, or until fully chilled and set, before slicing into 12 portions and serving.