In a food processor, add the flour, salt, sugar, and butter and pulse until it reaches pea-like pieces. Add in the ice water, a tablespoon at a time until it comes together (you likely won't use it all!). Form into two thick round disks, wrap in plastic wrap and refrigerate for 1 hour to set up.
Meanwhile, preheat oven to 350F.
Mix together the chia and almond milk and refrigerate for 20 minutes.
In a food processor, puree the chia egg (the chia and almond milk mixture), maple, sugar, cornstarch, vanilla, vinegar, vegan butter, salt and cinnamon.
Stir in the pecan halves.
Roll the first dough disk out to less than 1/4 inch and fit into a 9 inch pie plate. Prick the bottom. Chill until firm for about 30 minutes.
Roll the second disk out and using a cookie cutter (or free-form with a knife) cut out leaf shapes.
Pour the filling into the shell and press the leaf shapes all around the edge.
Bake for about 1 hour or until it just gently jiggles in the center. After the first 20 minutes, you’ll likely want to cover the edges with tin foil to prevent the crust from overbrowning.
Allow to cool completely before slicing and serving.