Preheat your oven to 350°F (175°C). Combine the almond flour, melted butter, erythritol, and salt in a bowl and mix well. Press firmly into the bottom and up the sides of a 9-inch pie dish. Par-bake for 10 minutes, then set aside.
Spread the pecan halves on a separate baking sheet and toast in the oven for 5 to 7 minutes until fragrant and slightly darkened. Remove and set aside.
In a medium saucepan, melt the butter over medium heat. Add the brown erythritol and stir continuously for 2 to 3 minutes until it dissolves and the mixture darkens slightly.
Remove the saucepan from the heat and stir in the heavy cream. The mixture will bubble, so stir carefully until smooth. Let it cool for 3 to 4 minutes.
Slowly whisk in the beaten eggs, vanilla extract, and salt until fully combined. Fold in the toasted pecans.
Pour the filling into the par-baked crust and arrange the pecans evenly across the top.
Bake for 30 to 35 minutes, until the edges are set and the center has just a slight jiggle. If the crust edges brown too quickly, cover them with foil.
Let the pie cool completely on a wire rack, then refrigerate for at least 2 hours before slicing for the cleanest cuts.
