Preheat the oven to 350°F and line an 8x8-inch pan with parchment paper. Mix the almond flour, erythritol, salt and melted butter, press firmly into the pan and bake for 10 to 12 minutes until golden at the edges. Cool completely.
Sprinkle the gelatin over the cold water and let it bloom. Heat 1 cup heavy cream and the almond milk in a saucepan until steaming.
Whisk the xanthan gum into the powdered erythritol, then whisk this with the egg yolks until pale. Slowly stream in the hot cream while whisking, then pour everything back into the saucepan.
Cook over medium-low heat, stirring constantly, for 4 to 6 minutes until thick enough to coat the spoon. Off the heat, stir in the bloomed gelatin, butter and vanilla until melted.Pour into a bowl, press plastic wrap onto the surface and chill for 40 to 45 minutes, until cool but not set.
Whip 3/4 cup heavy cream to stiff peaks. Whisk the cooled custard until smooth, then fold in the whipped cream.
Spread the vanilla cream over the crust and chill for 2 hours, until set.
Heat 1/3 cup heavy cream until steaming and pour it over the chocolate chips and butter. Let sit for 2 minutes, stir until glossy, then cool for 10 minutes.
Pour the ganache over the cream layer and spread gently. Chill for 1 more hour, then slice into 16 bars.