Prepare the Crust: In a medium bowl, combine the almond flour, erythritol, salt, and melted butter. Mix until it forms a crumbly dough. If using pecans, stir them in. Press this mixture evenly into the bottom of a 9x13-inch baking dish. Place in the refrigerator to chill while you prepare the next layers.

Make the Cream Cheese Layer: In a large mixing bowl, beat the softened cream cheese with powdered erythritol and vanilla extract until smooth and creamy. In a separate bowl, whip 1 cup of heavy cream until stiff peaks form. Gently fold the whipped cream into the cream cheese mixture until fully incorporated. Spread this layer evenly over the chilled crust. Return to the fridge.

Prepare the Chocolate Pudding Layer: In a saucepan over medium heat, whisk together 2 cups heavy cream, erythritol, cocoa powder, and vanilla extract. Heat until just simmering, then sprinkle in the xanthan gum while whisking constantly to avoid lumps. Continue cooking for 2-3 minutes until thickened. Remove from heat and let cool slightly. Pour over the cream cheese layer, spreading evenly. Chill for at least 30 minutes.

Whip the Topping: In a clean bowl, whip 1 ½ cups heavy cream with powdered erythritol and vanilla until stiff peaks form. Spread this fluffy layer over the set chocolate pudding.

Garnish and Chill: Sprinkle sugar-free chocolate shavings and pecan halves on top. Cover and refrigerate for at least 2 hours, or overnight for best results.

Serve: Cut into squares and enjoy! Store leftovers in an airtight container in the fridge for up to 5 days.