01 - Preheat oven to 325°F. Line the bottom of a 9-inch springform pan with parchment paper and set aside.
02 - In a mixing bowl, combine almond flour, erythritol, melted butter, cinnamon, and salt. Stir until a crumbly dough forms. Press the mixture evenly and firmly into the bottom of the prepared springform pan. Bake for 10 minutes, then remove and allow to cool completely.
03 - In a small saucepan, combine chopped rhubarb, erythritol, lemon juice, and water. Cook over medium heat, stirring frequently, until the rhubarb breaks down and the mixture thickens to a jam-like consistency, about 8 minutes. Remove from heat and set aside to cool.
04 - In a large bowl, beat the softened cream cheese and erythritol with an electric mixer until completely smooth and free of lumps. Add sour cream and blend until incorporated. Add eggs one at a time, mixing just until each is combined. Stir in vanilla extract and lemon zest. Be careful not to overmix to avoid incorporating excess air.
05 - Pour the cream cheese filling over the cooled crust, spreading evenly. Spoon small dollops of the cooled rhubarb compote across the surface. Using a butter knife or skewer, gently drag through the compote dollops to create decorative swirls throughout the batter.
06 - Tap the springform pan gently on the counter to release any trapped air bubbles. Place in the preheated oven and bake for 45 to 50 minutes, until the edges are firmly set and the center has a slight jiggle. Turn off the oven, crack the door open, and let the cheesecake rest inside for 1 hour to cool gradually and prevent cracking.
07 - Remove the cheesecake from the oven and transfer to the refrigerator. Chill for at least 2 hours, or until the filling is completely set. Slice into 12 portions and serve chilled.