Preheat & prep pan: Preheat oven to 325°F (160°C). Grease a 9-inch springform and line the base with parchment; wrap the outside in foil.

Make crust: Mix almond flour, powdered allulose, and salt. Stir in melted butter until crumbs hold. Press into pan base firmly. Blind-bake 8–10 minutes until lightly golden. Cool.

Make caramel: In a saucepan over medium-low heat, combine 200 g heavy cream, 56 g butter, and 80 g allulose. Stir until dissolved, simmer gently and reduce 12–18 minutes until amber and slightly thickened. Remove from heat and add vanilla + pinch salt. Reserve 120–150 g for swirling; cool.

Make filling: Beat room-temp cream cheese until smooth. Add 100 g allulose and mix. Add eggs one at a time on low speed. Fold in 120 g heavy cream, 120 g sour cream, vanilla, and salt. Mix until smooth (avoid overwhipping).

Assemble: Pour two-thirds of batter into crust. Drop spoonfuls of reserved caramel over batter; pour remaining batter on top. Dollop remaining caramel and swirl gently with a skewer (2–3 passes).

Bake in water bath: Wrap springform with foil. Place in roasting pan; pour hot water into roasting pan to halfway up the pan sides. Bake 55–70 minutes until edges set and center slightly jiggles.

Cool & chill: Turn off oven; crack door and let cool inside 30–60 minutes. Transfer to wire rack to cool completely, then chill at least 6 hours or overnight.

Serve: Thin extra caramel if needed, drizzle over slices, garnish and serve. Store refrigerated.