01 - Preheat the oven to 325°F. Line the bottom of a 9-inch springform pan with parchment paper and lightly grease the sides.
02 - In a mixing bowl, combine the almond flour, erythritol, melted butter, cinnamon, and salt. Stir until a crumbly, cohesive dough forms. Press the mixture evenly and firmly into the bottom of the prepared springform pan. Bake for 10 minutes, then remove and set aside to cool completely.
03 - In a small saucepan, combine the 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 let 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 the sour cream and blend well. Incorporate the eggs one at a time, mixing just until each is fully combined. Stir in the vanilla extract and lemon zest. Avoid overmixing to prevent excess air incorporation.
05 - Pour the cream cheese filling over the cooled crust, spreading it into an even layer. Drop small spoonfuls of the rhubarb compote across the surface. Use a butter knife or skewer to gently swirl the compote through the filling in a figure-eight motion.
06 - Tap the springform pan firmly on the counter a few times to release trapped air bubbles. Place in the oven and bake for 45 to 50 minutes, until the edges are set and the center still 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 - Transfer the cheesecake to the refrigerator and chill for at least 2 hours, or until fully set. Slice into 12 even portions and serve chilled.