01 - Preheat oven to 325°F. Line the bottom of a 9-inch springform pan with parchment paper.
02 - In a bowl, combine almond flour, erythritol, melted butter, cinnamon, and salt. Mix until a crumbly dough forms. Press the mixture evenly into the bottom of the prepared pan. Bake for 10 minutes, then remove and let cool.
03 - In a small saucepan, combine rhubarb, erythritol, lemon juice, and water. Cook over medium heat, stirring frequently, until the rhubarb softens and the mixture reaches a jam-like consistency, about 8 minutes. Set aside to cool.
04 - In a large bowl, beat the cream cheese and erythritol until smooth and creamy. Add sour cream and blend. Add eggs one at a time, mixing after each addition. Stir in vanilla extract and lemon zest until just combined. Do not overmix.
05 - Pour the filling over the cooled crust. Spoon small dollops of rhubarb compote onto the surface. Use a knife or skewer to gently swirl the compote into the batter in a figure-eight motion.
06 - Tap the pan gently on the counter to release any trapped air bubbles. Bake for 45 to 50 minutes, until the edges are set and the center has a slight jiggle. Turn off the oven, crack the door open, and let the cheesecake cool inside for 1 hour.
07 - Remove the cheesecake from the oven and transfer to the refrigerator. Chill for at least 2 hours, or until fully set, before slicing and serving.