Prep the pan: Heat oven to 325°F (163°C). Line the bottom of a 9-inch springform pan with parchment.
Lightly grease the sides.
Make the crust: In a bowl, mix almond flour, granulated sweetener, and salt. Stir in melted butter and vanilla until it resembles damp sand. Press firmly into the bottom of the pan.
Bake 8–10 minutes until lightly golden. Cool while you make the filling.
Beat the cream cheese: In a large bowl, beat cream cheese on medium speed for 1–2 minutes until smooth and lump-free. Scrape the bowl.
Add sweetener and flavor: Beat in powdered sweetener, vanilla, and salt until creamy.
Add sour cream and mix on low just until combined.
Incorporate eggs: Add eggs one at a time on low speed, mixing just until each is incorporated. Avoid overbeating to limit air bubbles.
Fill and smooth: Pour batter over the cooled crust. Tap the pan gently on the counter to release air bubbles.
Run a knife through the batter to pop any large pockets.
Bake gently: Place the springform on a baking sheet. Bake 45–55 minutes, until edges are set and the center has a slight wobble. The top should look matte, not wet.
Cool slowly: Turn off the oven, crack the door, and let the cheesecake sit inside for 30 minutes.
Then remove, run a thin knife around the edge, and cool to room temperature.
Chill to set: Cover and refrigerate at least 6 hours, preferably overnight, for the best texture and clean slices.
Make the salted caramel: In a small saucepan, combine allulose and water over medium heat. Cook, swirling occasionally, until it turns a deep amber, 4–6 minutes. Remove from heat, whisk in butter, then slowly whisk in warm cream.
Return to low heat and simmer 1–2 minutes until slightly thickened. Stir in vanilla and salt. Cool until pourable but not hot.
Finish and serve: Release the cheesecake from the pan.
Spoon or drizzle caramel over the top, letting some drip down the sides. Sprinkle with extra flaky salt if you like. Slice with a hot, dry knife for neat edges.