Preheating and Pan Prep: Preheat your air fryer to 350°F for 5 minutes. Take a large sheet of parchment paper and crumple it tightly into a ball, then unfold it. Press the wrinkled paper firmly into a 6-inch cake pan, allowing the excess to pleat naturally and extend past the top rim of the pan.
Smooth Blending: Place the room-temperature cream cheese, white sugar, palm sugar, eggs, heavy cream, flour, vanilla, salt, and lemon juice into a blender or food processor. Blend on medium speed just until the batter is entirely smooth, fluid, and free of any lumps. Do not over-blend past this point to avoid introducing excess air bubbles.
The Pour: Pour the glossy batter straight into your prepared, parchment-lined cake pan, tapping the pan gently on the counter once to release any large trapped bubbles.
The Two-Stage Bake: Place the pan into the air fryer basket and bake at 350°F for 25 minutes. As soon as the timer ends, immediately increase the air fryer temperature to 400°F and bake for an additional 5 minutes until the top is a deep, scorched amber-brown.
The Rest: Carefully check the center with a digital thermometer; it should register an internal temperature of 185°F. The cake will look highly unstable and jiggly in the middle. Remove the pan from the air fryer and place it on a wire rack on your counter. Let it cool undisturbed for at least 2 hours before slicing.