Preheat the oven to 350F and line a 9 inch springform pan with parchment. Combine the almond flour, melted butter, sweetener, vanilla and salt, press firmly into the pan and bake for 10 minutes. Cool and reduce the oven to 325F.
Beat the cream cheese and sweetener for 2 minutes until smooth. Add the eggs one at a time on low speed, then mix in the sour cream and vanilla just until combined.
Transfer half the batter to a second bowl. Stir the orange zest, orange extract and food coloring into one bowl to make the orange layer, leaving the other bowl as vanilla.
Pour the orange batter over the crust and smooth it out. Gently spoon the vanilla batter on top in dollops and spread carefully so the layers stay separate, then drag a skewer through once or twice for a soft swirl on top.
Bake for 50 to 55 minutes until the edges are set and the center jiggles slightly. Turn the oven off, crack the door and cool inside for 1 hour, then refrigerate for at least 6 hours.
Whip the cold heavy cream with the sweetener and vanilla bean paste to stiff peaks. Spread or pipe it over the chilled cheesecake.
Finish with a little extra orange zest on top and serve cold for the full creamsicle effect.