Crust
Preheat the oven to 325ºF.
In a medium bowl, whisk together the pecan flour, sweetener, and salt. Stir in the butter until the mixture begins to clump together.
Press evenly into the bottom and up the sides of a glass or ceramic pie pan. If the pan is deep dish, only go about 3/4 of the way up.
Bake about 15 minutes, or until the edges are becoming browned. Remove and let cool completely in the pan, then place in the freezer.
Butter Pecan Ice Cream
In a medium saucepan over medium heat, combine 3/4 cup of the whipping cream, the almond milk, powdered Swerve, and allulose. Bring to a strong simmer, then reduce the heat and continue to simmer gently for 30 minutes.
Remove from heat and whisk in the vanilla extract. Sprinkle the surface with the xanthan gum while whisking vigorously to combine. Let the mixture cool completely.
Meanwhile, melt the butter in a medium skillet over medium heat. Once melted, add the pecans, sweetener, and salt and toss to coat. Cook for 2 minutes or so to lightly toast the pecans. Then remove from heat and let cool completely.
Once both the condensed milk is cool, place the remaining heavy cream in a large bowl and beat until it holds stiff peaks. Carefully fold in the condensed milk until no streaks remain. Stir in the cooled pecans.
Spread the mixture evenly in the chilled crust and freeze at least 8 hours, preferably overnight.