Preheat the oven to 350F and line a 9 inch springform pan with parchment. Mix the almond flour, melted butter, sweetener, vanilla and salt, press 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. Pour over the crust.
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 4 hours.
Make the pastry cream. Whisk the egg yolks, sweetener and xanthan gum in a bowl. Heat the heavy cream and almond milk in a saucepan until steaming, then slowly whisk it into the yolks.
Return everything to the saucepan and cook over medium low heat, whisking constantly, for 4 to 6 minutes until thick enough to coat a spoon. Remove from the heat, stir in the butter and vanilla bean paste, and cool for 15 minutes.
Spread the pastry cream in an even layer over the chilled cheesecake, leaving the springform ring on so it holds a clean edge. Refrigerate for 1 hour until set.
Heat the heavy cream and butter until steaming, pour over the chocolate chips, wait 2 minutes and stir until glossy. Cool for 5 minutes, then pour over the pastry cream and tilt the pan to cover. Chill for 30 minutes, then release the ring and slice.