Preheat the oven to 350 degrees F (175 degrees C).

Mix almond flour and 4 tablespoons melted butter together in a small bowl. Press into an ungreased 9-inch pie pan. Chill in the refrigerator while preparing the filling.

Combine sweetener, syrup, eggs, 2 tablespoons melted butter, and vanilla in a medium bowl. Stir in pecans. Pour mixture into pie crust.

Bake in the preheated oven until filling is set, about 45 minutes.